FN ISI Export Format VR 1.0 PT Journal AU Bezerra, CG de Araujo, JM Chesman, C Albuquerque, EL TI Magnetization in quasiperiodic magnetic multilayers with biquadratic exchange coupling SO JOURNAL OF APPLIED PHYSICS NR 28 AB A theoretical study of the magnetization curves of quasiperiodic magnetic multilayers is presented. We consider structures composed by ferromagnetic films (Fe) with interfilm exchange coupling provided by intervening nonferromagnetic layers (Cr). The theory is based on a realistic phenomenological model, which includes the following contributions to the free magnetic energy: Zeeman, cubic anisotropy, bilinear, and biquadratic exchange energies. The experimental parameters used here are based on experimental data recently reported, which contain sufficiently strong biquadratic exchange coupling. (C) 2001 American Institute of Physics. CR AZEVEDO A, 1996, PHYS REV LETT, V76, P4837 BAIBICH MN, 1988, PHYS REV LETT, V61, P2472 BEZERRA CG, 1999, PHYS REV B, V60, P9264 BEZERRA CG, 1999, PHYSICA A, V267, P124 BEZERRA CG, 1998, PHYSICA A, V255, P285 BEZERRA CG, 1997, PHYSICA A, V245, P379 CHESMAN C, 1998, PHYS REV B, V58, P101 DEOLIVEIRA PMC, 1996, PHYSICA A, V227, P206 FOLKERTS W, 1992, J MAGN MAGN MATER, V111, P306 GALLAGHER WJ, 1997, J APPL PHYS 2A, V81, P3741 GRUNBERG P, 1986, PHYS REV LETT, V57, P2442 HORST R, 1995, HDB GLOBAL OPTIMIZAT KIRKPATRICK S, 1983, SCIENCE, V220, P671 KOHMOTO M, 1987, PHYS REV B, V35, P1020 KOHMOTO M, 1987, PHYS REV LETT, V58, P2436 PARKIN SSP, 1990, PHYS REV LETT, V64, P2304 PRESS WH, 1998, NUMERICAL RECIPES QUILICHINI M, 1997, REV MOD PHYS, V69, P277 REZENDE SM, 1998, J APPL PHYS, V84, P958 RUHRIG M, 1991, PHYS STATUS SOLIDI A, V125, P635 SHECHTMAN D, 1984, PHYS REV LETT, V53, P1951 SORENSEN ES, 1990, PHYS REV B, V42, P754 STEINHARDT PJ, 1997, PHYSICS QUASICRYSTAL TURBAN L, 1994, J PHYS A-MATH GEN, V27, P6349 VASCONCELOS MS, 1998, J PHYS-CONDENS MAT, V10, P5839 VASCONCELOS MS, 1998, PHYS REV B, V57, P2826 VASCONCELOS MS, 1999, PHYSICA A, V268, P165 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 0 BP 2286 EP 2292 PG 7 JI J. Appl. Phys. PY 2001 PD FEB 15 VL 89 IS 4 GA 397HY J9 J APPL PHYS UT ISI:000166688300045 ER PT Journal AU te Velthuis, SGE Jiang, JS Felcher, GP TI Switching of the exchange bias in Fe/Cr(211) double- superlattice structures SO APPLIED PHYSICS LETTERS NR 15 AB The reversal of the direction of the exchange bias in a "double-superlattice" system which consists of an Fe/Cr antiferromagnetic (AF) superlattice which is ferromagnetically coupled with an Fe/Cr ferromagnetic (F) superlattice through a Cr spacer layer, is observed. Magnetometry and polarized neutron reflectometry show that a switch in the bias direction occurs at a field (similar to 447 Oe) well below the field (14 kOe) necessary to saturate the AF superlattice and well below the field (2 kOe) where the AF superlattice initiates a spin- flop transition. The switching of the exchange bias cannot be explained in terms of a model of uniform rotation, but rather by breakdown into domains and reversal of the AF layers. The transparency of magnetic behavior of the double superlattice may be useful in understanding the behavior of traditional exchange bias systems. (C) 2000 American Institute of Physics. [S0003- 6951(00)00240-0]. CR DANTAS AL, 1999, PHYS REV B, V59, P1223 FULLERTON EE, 1994, J APPL PHYS, V75, P6461 FULLERTON EE, 1993, PHYS REV B, V48, P15755 JIANG JS, 2000, J VAC SCI TECHNOL 1, V18, P1264 JIANG JS, 2000, PHYS REV B, V61, P9653 LAAR L, UNPUB MALOZEMOFF AP, 1987, PHYS REV B, V35, P3679 MEIKLEJOHN WH, 1957, PHYS REV, V105, P904 NOGUES J, 2000, PHYS REV B, V61, PR6455 RAKHMANOVA S, 1998, PHYS REV B, V57, P476 SCHULTHESS TC, 1998, PHYS REV LETT, V81, P4516 STILES MD, 1999, PHYS REV B, V59, P3722 TAKANO K, 1997, PHYS REV LETT, V79, P1130 TEVELTHUIS SGE, 1999, APPL PHYS LETT, V75, P4174 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 1 BP 2222 EP 2224 PG 3 JI Appl. Phys. Lett. PY 2000 PD OCT 2 VL 77 IS 14 GA 357WZ J9 APPL PHYS LETT UT ISI:000089524900048 ER PT Journal AU Diaz-Ortiz, A Sanchez, JM Moran-Lopez, JL TI Phase transitions in confined antiferromagnets SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH NR 23 AB Confinement effects on the phase transitions in antiferromagnets are studied as a function of the surface coupling v and the surface field h for b.c.c.(110) films. Unusual topologies for the phase diagram are attained for particular combinations of v and h. It is shown that some of the characteristics of the finite-temperature behavior of the system are driven by its low-temperature properties and consequently can be explained in terms of a ground-state analysis. Cluster variation free energies are used for the investigation of the finite temperature behavior. CR BINDER K, 1992, J CHEM PHYS, V96, P1444 BINDER K, 1983, PHASE TRANSITIONS CR DIAZORTIZ A, 1997, COMP MATER SCI, V8, P79 DIAZORTIZ A, IN PRESS DIAZORTIZ A, 1998, PHYS REV LETT, V81, P1146 DIAZORTIZ A, 1998, SOLID STATE COMMUN, V107, P285 DOSCH H, 1992, CRIT PHENOMENA SURFA, V126 DOWBEN PA, 1990, SURFACE SEGRETATION DREWITZ A, 1997, PHYS REV LETT, V78, P1090 EVANS R, 1990, J PHYS-CONDENS MAT, V2, P8989 FISHER ME, 1981, J CHEM PHYS, V75, P5857 FULLERTON EE, 1993, PHYS REV B, V48, P15755 KEFFER F, 1973, PHYS REV LETT, V31, P1061 KIKUCHI R, 1951, PHYS REV, V81, P998 LEIDL R, 1998, PHYS REV B, V57, P1908 MICHELETTI C, 1997, J PHYS A-MATH GEN, V30, PL233 MICHELETTI C, 1999, PHYS REV B, V59, P6239 MILLS DL, 1968, PHYS REV LETT, V20, P18 NAKANISHI H, 1983, J CHEM PHYS, V78, P3279 NAKANISHI H, 1982, PHYS REV LETT, V49, P1565 TRALLORI L, 1998, PHYS REV B, V57, P5923 TRALLORI L, 1994, PHYS REV LETT, V72, P1925 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 0 BP 389 EP 394 PG 6 JI Phys. Status Solidi B-Basic Res. PY 2000 PD JUL VL 220 IS 1 GA 344PV J9 PHYS STATUS SOLIDI B-BASIC RE UT ISI:000088768800069 ER PT Journal AU Jiang, JS Felcher, GP Inomata, A Goyette, R Nelson, CS Bader, SD TI Exchange bias in Fe/Cr double superlattices SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS NR 27 AB Utilizing the oscillatory interlayer exchange coupling in Fe/Cr superlattices, we have constructed "double superlattice" structures where a ferromagnetic (F) and an antiferromagnetic (BF) Fe/Cr superlattice are coupled through a Cr spacer. The minor hysteresis loops in the magnetization are shifted from zero field, i.e., the F superlattice is exchange biased by the AF one. The double superlattices are sputter deposited with (211) epitaxy and possess uniaxial in-plane magnetic anisotropy. The magnitude of the bias field is satisfactorily described by the classic formula for collinear spin structures. The coherent structure and insensitivity to atomic-scale roughness makes it possible to determine the spin distribution by polarized neutron reflectivity, which confirms that the spin structure is collinear. The magnetic reversal behavior of the double superlattices suggests that a realistic model of exchange bias needs to address the process of nucleating local reverse domains. (C) 2000 American Vacuum Society. [S0734- 2101(00)02204-1]. CR BRUNO P, 1995, PHYS REV B, V52, P411 CAMLEY RE, 1999, J VAC SCI TECHNOL 1, V17, P1335 DIENY B, 1991, PHYS REV B, V43, P1297 FELCHER GP, 1993, J MAGN MAGN MATER, V121, P105 FOLKERTS W, 1991, J MAGN MAGN MATER, V94, P302 FULLERTON EE, 1994, J APPL PHYS, V75, P6461 FULLERTON EE, 1993, PHYS REV B, V48, P15755 JUNGBLUT R, 1995, J MAGN MAGN MATER, V148, P300 KIWI M, 1999, EUROPHYS LETT, V48, P573 KOON NC, 1997, PHYS REV LETT, V78, P4865 MALOZEMOFF AP, 1987, PHYS REV B, V35, P3679 MAURI D, 1987, J APPL PHYS, V62, P3047 MEIKLEJOHN WH, 1962, J APPL PHYS, V33, P1328 MEIKLEJOHN WH, 1957, PHYS REV, V105, P904 NIKITENKO VI, 1998, PHYS REV B, V57, PR8111 NOGUES J, 1999, J MAGN MAGN MATER, V192, P203 PARKIN SSP, 1991, PHYS REV B, V44, P7131 PARKIN SSP, 1990, PHYS REV B, V42, P10583 PARKIN SSP, 1990, PHYS REV LETT, V64, P2304 SCHULTHESS TC, 1998, PHYS REV LETT, V81, P4516 STILES MD, 1999, PHYS REV B, V59, P3722 SUHL H, 1998, PHYS REV B, V58, P258 TAKANO K, 1997, PHYS REV LETT, V79, P1130 TANG C, 1984, J APPL PHYS, V55, P2226 TEVELTHUIS SGE, 1999, APPL PHYS LETT, V75, P4174 WANG RW, 1994, PHYS REV LETT, V72, P920 ZABEL H, 1994, PHYSICA B, V198, P156 TC 2 BP 1264 EP 1268 PG 5 JI J. Vac. Sci. Technol. A-Vac. Surf. Films PY 2000 PD JUL-AUG VL 18 IS 4 PN 1 GA 335ZH J9 J VAC SCI TECHNOL A UT ISI:000088276800044 ER PT Journal AU Yan, SS Grunberg, P Mei, M TI Magnetic phase diagrams of the trilayers with the noncollinear coupling in the form of the proximity magnetism model SO JOURNAL OF APPLIED PHYSICS NR 18 AB The magnetic phase diagrams of Fe/Mn/Fe trilayers with the noncollinear interlayer coupling in the form of the proximity magnetism model were theoretically studied. The C+-C- phase diagram in the remanent magnetization state predicts very rich spin configurations. The H-C+ and H-C- phase diagrams show that the spin configurations of Fe/Mn/Fe trilayers depend strongly on the external magnetic field, the anisotropy of Fe layers, and the coupling coefficients C+ and C-. Our experimental results of noncollinear spin configurations of Fe/Mn/Fe trilayers strongly support the magnetic phase diagrams based on the proximity magnetism model. (C) 2000 American Institute of Physics. [S0021-8979(00)00914-2]. CR ALMEIDA NS, 1995, PHYS REV B, V52, P13504 CELINSKI Z, 1995, J MAGN MAGN MATER, V145, PL1 DIENY B, 1990, J PHYS-CONDENS MAT, V2, P159 FILIPKOWSKI ME, 1995, PHYS REV LETT, V75, P1847 FONSECA TL, 1998, PHYS REV B, V57, P76 FUSS A, 1992, J MAGN MAGN MATER, V103, PL221 GRUNBERG P, 1986, PHYS REV LETT, V57, P2442 KOSTYUCHENKO VV, 1998, PHYS REV B, V57, P5951 NORTEMANN FC, 1992, PHYS REV B, V46, P10847 PIERCE DT, 1999, J MAGN MAGN MATER, V200, P290 RODMACQ B, 1993, PHYS REV B, V48, P3556 RUHRIG M, 1991, PHYS STATUS SOLIDI A, V125, P635 SCHAFER M, 1995, J APPL PHYS, V77, P6432 SCHREYER A, 1995, PHYS REV B, V52, P16066 SLONCZEWSKI JC, 1995, J MAGN MAGN MATER, V150, P13 WANG RW, 1994, PHYS REV LETT, V72, P920 WOLF JA, 1993, J MAGN MAGN MATER, V121, P253 YAN SS, 1999, PHYS REV B, V59, PR1164 TC 1 BP 983 EP 987 PG 5 JI J. Appl. Phys. PY 2000 PD JUL 15 VL 88 IS 2 GA 329DA J9 J APPL PHYS UT ISI:000087889800060 ER PT Journal AU Jiang, JS Felcher, GP Inomata, A Goyette, R Nelson, C Bader, SD TI Exchange-bias effect in Fe/Cr(211) double superlattice structures SO PHYSICAL REVIEW B NR 28 AB Shifted hysteresis loops characteristic of the exchange-bias effect between a ferromagnet (F) and an antiferromagnet (AF) are demonstrated in "double-superlattice" structures. Utilizing the well-established oscillatory interlayer exchange coupling in Fe/Cr, we have constructed [Fe/Cr](AF)/Cr/[Fe/Cr](F) double superlattices where Fe/Cr superlattices with appropriate Cr- spacer thickness represent the F and the AF. The double superlattices are (211)-oriented epitaxial films sputter grown on single-crystal MgO(110) substrates. The AF/F interface is coherent compared to conventional exchange-bias interfaces consisting of dissimilar AF and F phases. Magnetization results show that AF/F exchange coupling affects the nucleation of reverse magnetic domains, and that the magnitude of the exchange-bias field is given directly by the classic formula for collinear spin structures. The collinear spin distribution is confirmed by polarized neutron reflectivity. CR BERKOWITZ AE, 1965, J APPL PHYS, V36, P3330 DIENY B, 1991, PHYS REV B, V43, P1297 FELCHER GP, 1993, J MAGN MAGN MATER, V121, P105 FOLKERTS W, 1991, J MAGN MAGN MATER, V94, P302 FULLERTON EE, 1994, J APPL PHYS, V75, P6461 FULLERTON EE, 1993, PHYS REV B, V48, P15755 GOKEMEIJER NJ, 1997, PHYS REV LETT, V79, P4270 JUNGBLUT R, 1995, J MAGN MAGN MATER, V148, P300 KOON NC, 1997, PHYS REV LETT, V78, P4865 KOUVEL JS, 1960, J PHYS CHEM SOLIDS, V16, P132 MALOZEMOFF AP, 1987, PHYS REV B, V35, P3679 MAURI D, 1987, J APPL PHYS, V62, P3047 MEIKLEJOHN WH, 1962, J APPL PHYS, V33, P1328 MEIKLEJOHN WH, 1957, PHYS REV, V105, P904 MORAN TJ, 1998, APPL PHYS LETT, V72, P617 MORAN TJ, 1995, J APPL PHYS, V78, P1887 NOGUES J, 1996, APPL PHYS LETT, V68, P3186 NOGUES J, 1999, J MAGN MAGN MATER, V192, P203 PARKIN SSP, 1991, PHYS REV B, V44, P7131 PARKIN SSP, 1990, PHYS REV B, V42, P10583 PARKIN SSP, 1990, PHYS REV LETT, V64, P2304 SCHULTHESS TC, 1998, PHYS REV LETT, V81, P4516 SPERIOSU V, UNPUB TAKANO K, 1997, PHYS REV LETT, V79, P1130 TANG C, 1984, J APPL PHYS, V55, P2226 UNGURIS J, 1991, PHYS REV LETT, V67, P140 WANG RW, 1994, PHYS REV LETT, V72, P920 ZABEL H, 1994, PHYSICA B, V198, P156 TC 3 BP 9653 EP 9656 PG 4 JI Phys. Rev. B PY 2000 PD APR 1 VL 61 IS 14 GA 303TW J9 PHYS REV B UT ISI:000086441800062 ER PT Journal AU Temst, K Kunnen, E Moshchalkov, VV Maletta, H Fritzsche, H Bruynseraede, Y TI Magnetic order and the spin-flop transition in Fe/Cr superlattices SO PHYSICA B NR 4 AB We have studied the structural and magnetic properties of MBE- prepared epitaxial Fe/Cr(001) oriented superlattices. The samples consist of 20 periods with 25 nm Fe and 1.3 nm Cr individual layer thicknesses. The samples were characterized by X-ray diffraction, while: the magnetic properties were determined by magnetoresistivity, magnetooptical Kerr effect, and polarized neutron reflectivity measurements. The transition from antiparallel to parallel alignment of the magnetizations in adjacent Fe layers was investigated using polarized neutron reflectivity measurements while applying a held parallel to the layers. A spin-flop transition due to the fourfold anisotropy in the Fe layers was observed at a field of 200 Oe. (C) 2000 Elsevier Science B.V. All rights reserved. CR ADENWALLA S, 1996, PHYS REV B, V53, P2474 MILLS DL, 1968, PHYS REV LETT, V20, P18 SCHREYER A, 1995, PHYS REV B, V52, P16066 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 0 BP 684 EP 685 PG 2 JI Physica B PY 2000 PD MAR VL 276 GA 303FZ J9 PHYSICA B UT ISI:000086413000311 ER PT Journal AU Zvezdin, AK Kostyuchenko, VV TI Nonlinear domain-wall dynamics in a system of two magnetic layers SO JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS NR 18 AB The nonlinear dynamics of the magnetization in a spin-valve structure is investigated. Equations describing the dynamics of the magnetization in such a structure are obtained. The stability of the solution corresponding to a motionless flat domain wall is investigated. The nonlinear domain-wall dynamics are investigated in the approximation of a strong exchange interaction between the magnetic layers and in the approximation of a large magnetostatic energy. In the former case the nonlinear dynamical equations are shown to be similar to the equations describing the dynamics of the magnetization in a weak ferromagnet, and in the latter case they are similar to the equations of motion of a magnetic vortex (i.e., a vertical Bloch line) in a domain wall. (C) 1999 American Institute of Physics. [S1063-7761(99)01710-2]. CR ALMEIDA NS, 1995, PHYS REV B, V52, P13504 ANDREEV AF, 1980, SOV PHYS USP, V23, P21 BARYAKHTAR VG, 1994, DYNAMICS TOPOLOGICAL BISHOP A, 1981, SOLITONY DEISTVII, P72 BRAUN OM, 1988, J PHYS C SOLID STATE, V21, P3881 KOSEVICH AM, 1983, NONLINEAR MAGNETIZAT KOSTYUCHENKO VV, 1998, PHYS REV B, V57, P5951 LANDAU L, 1935, PHYS Z SOWJETUNION, V8, P153 MALOZEMOFF AP, 1982, MAGNETIC DOMAIN WALL MICHELETTI C, 1997, J PHYS A-MATH GEN, V30, PL233 PAPANICOLAOU N, 1995, PHYS REV B, V51, P15062 SCHREYER A, 1995, PHYS REV B, V52, P16066 TRALLORI L, 1995, J PHYS CONDENS MATT, V7, PL451 WANG RW, 1994, PHYS REV B, V50, P3931 WANG RW, 1994, PHYS REV LETT, V72, P920 ZVEZDIN AK, 1979, JETP LETT, V29, P553 ZVEZDIN AK, 1997, PHYS SOLID STATE, V39, P155 ZVEZDIN AK, 1990, SOV PHYS JETP, V71, P597 TC 0 BP 734 EP 739 PG 6 JI J. Exp. Theor. Phys. PY 1999 PD OCT VL 89 IS 4 GA 254NJ J9 J EXP THEOR PHYS UT ISI:000083618800017 ER PT Journal AU Mills, DL TI Phase transitions in magnetic multilayers; statics and dynamics SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS NR 9 AB Magnetic multilayers which incorporate ultrathin ferromagnetic films are physical realizations of classical, one dimensional spin systems, with spins coupled via exchange mediated by spacer layers or interactions at. interfaces, and subject to anisotropy. Here by 'spin', we refer to the total spin angular momentum of an ultrathin film in the structure. Such systems can undergo a rich range of phase transitions, in reponse to an external magnetic field, or change in temperature. Since interfilm exchange is weak, modest magnetic fields can induce spin reorientation phase transitions. We thus have a new and diverse class of magnetic materials, with phase diagrams subject to design, since both thickness, composition, or growth conditions. The paper reviews selected examples, including recent studies of the dynamic response (AC susceptibility) of an antiferromagnetically coupled Fe/Cr system which undergoes the surface spin-flop transition. (C) 1999 Elsevier Science B.V. All rights reserved. CR CAMLEY RE, 1990, PHYS REV LETT, V64, P2703 FULLERTON EE, 1993, PHYS REV B, V48, P15755 KEFFER F, 1973, PHYS REV LETT, V31, P1061 MILLS DL, 1968, PHYS REV LETT, V20, P18 RAKHMANOVA S, 1998, PHYS REV B, V57, P476 RHYNE JJ, 1994, J MAGN MAGN MATER, V129, P39 SAJIEDDINE M, 1994, PHYS REV B, V49, P8815 TRALLORI L, 1994, PHYS REV LETT, V72, P1925 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 0 BP 334 EP 337 PG 4 JI J. Magn. Magn. Mater. PY 1999 PD JUN VL 199 GA 204TE J9 J MAGN MAGN MATER UT ISI:000080779600107 ER PT Journal AU Karadamoglou, J Papanicolaou, N TI Surface spin-flop transitions in a classical XYZ chain SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL NR 20 AB A surface spin-flop transition has recently been observed in a multilayer Fe/Cr film (superlattice) that may be effectively described by a classical antiferromagnetic chain with a single- ion anisotropy. In this paper we explore such a transition in a classical spin chain with exchange anisotropy. Our theoretical results may suggest the occurrence of a similar phenomenon in quantum spin chains doped with nonmagnetic ions. CR ASAKAWA H, 1998, PHYS REV B, V57, P8285 GAUDIN M, 1983, FONCTION ONDE BETHE GELFAND MP, 1997, PHYS REV B, V55, P11372 JIMBO M, 1995, NUCL PHYS B, V441, P437 JOHNSON JD, 1972, PHYS REV A, V6, P1613 KAPUSTIN A, 1996, J PHYS A-MATH GEN, V29, P1629 KEFFER F, 1973, PHYS REV LETT, V31, P1061 MICHELETTI C, 1999, IN PRESS PHYS REV B MICHELETTI C, 1997, J PHYS A-MATH GEN, V30, PL233 MILLS DL, 1968, PHYS REV, V171, P488 MILLS DL, 1968, PHYS REV LETT, V20, P18 PAPANICOLAOU N, 1999, J PHYS-CONDENS MAT, V11, P59 PAPANICOLAOU N, 1998, J PHYS-CONDENS MAT, V10, PL131 PAPANICOLAOU N, 1995, PHYS REV B, V51, P15062 RAKHMANOVA S, 1998, PHYS REV B, V57, P476 TRALLORI L, 1995, J PHYS CONDENS MATT, V7, PL451 TRALLORI L, 1998, PHYS REV B, V57, P5923 TRALLORI L, 1994, PHYS REV LETT, V72, P1925 WANG RW, 1996, PHYS REV B, V53, P2627 WANG RW, 1994, PHYS REV LETT, V72, P920 TC 1 BP 3275 EP 3281 PG 7 JI J. Phys. A-Math. Gen. PY 1999 PD MAY 7 VL 32 IS 18 GA 198KY J9 J PHYS-A-MATH GEN UT ISI:000080424200007 ER