Surface spin disorder in NiFe2O4 nanoparticles

被引:1548
作者
Kodama, RH [1 ]
Berkowitz, AE [1 ]
McNiff, EJ [1 ]
Foner, S [1 ]
机构
[1] FRANCIS BITTER NATL MAGNET LAB, CAMBRIDGE, MA 02139 USA
关键词
D O I
10.1103/PhysRevLett.77.394
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Nickel ferrite nanoparticles exhibit anomalous magnetic properties at low temperatures: low magnetization with a large differential susceptibility at high fields, hysteresis loops which are open up to 160 kOe, time-dependent magnetization in 70 kOe applied field, and shifted hysteresis loops after field cooling. We propose a model of the magnetization within these particles consisting offerrimagnetically aligned core spins and a spin-glass-like surface layer. We find that qualitative features of this model are reproduced by a numerical calculation of the spin distribution. Implications of this model for possible macroscopic quantum tunneling in these materials are discussed.
引用
收藏
页码:394 / 397
页数:4
相关论文
共 15 条
[1]   MACROSCOPIC QUANTUM TUNNELING IN MAGNETIC PROTEINS [J].
AWSCHALOM, DD ;
SMYTH, JF ;
GRINSTEIN, G ;
DIVINCENZO, DP ;
LOSS, D .
PHYSICAL REVIEW LETTERS, 1992, 68 (20) :3092-3095
[2]  
BARBARA B, 1992, N-HOLLAND D, P235
[3]   PROPERTIES OF MAGNETIC FLUID PARTICLES [J].
BERKOWITZ, AE ;
LAHUT, JA ;
VANBUREN, CE .
IEEE TRANSACTIONS ON MAGNETICS, 1980, 16 (02) :184-190
[4]   SPIN PINNING AT FERRITE-ORGANIC INTERFACES [J].
BERKOWITZ, AE ;
LAHUT, JA ;
JACOBS, IS ;
LEVINSON, LM ;
FORESTER, DW .
PHYSICAL REVIEW LETTERS, 1975, 34 (10) :594-597
[5]   QUANTUM TUNNELING OF MAGNETIZATION IN SMALL FERROMAGNETIC PARTICLES [J].
CHUDNOVSKY, EM ;
GUNTHER, L .
PHYSICAL REVIEW LETTERS, 1988, 60 (08) :661-664
[6]   NONCOLLINEAR SPIN ARRANGEMENT IN ULTRAFINE FERRIMAGNETIC CRYSTALLITES [J].
COEY, JMD .
PHYSICAL REVIEW LETTERS, 1971, 27 (17) :1140-+
[7]   DETERMINATION OF F(0) FOR FINE MAGNETIC PARTICLES [J].
DICKSON, DPE ;
REID, NMK ;
HUNT, C ;
WILLIAMS, HD ;
ELHILO, M ;
OGRADY, K .
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 1993, 125 (03) :345-350
[8]   MAGNETIZATION REVERSAL IN COBALT-PHOSPHORUS FILMS [J].
HUGHES, GF .
JOURNAL OF APPLIED PHYSICS, 1983, 54 (09) :5306-5313
[9]   LOW-TEMPERATURE MAGNETIC-RELAXATION OF ORGANIC COATED NIFE2O4 PARTICLES [J].
KODAMA, RH ;
SEAMAN, CL ;
BERKOWITZ, AE ;
MAPLE, MB .
JOURNAL OF APPLIED PHYSICS, 1994, 75 (10) :5639-5641
[10]   POLARIZED NEUTRON STUDY OF THE MAGNETIZATION DENSITY DISTRIBUTION WITHIN A COFE2O4 COLLOIDAL PARTICLE .2. [J].
LIN, D ;
NUNES, AC ;
MAJKRZAK, CF ;
BERKOWITZ, AE .
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 1995, 145 (03) :343-348