Interplay between reversible and irreversible magnetic phase transitions in polycrystalline Gd5Ge4

作     者：H. Tang V. K. Pecharsky K. A. Gschneidner, Jr. A. O. Pecharsky 

作者机构：Materials and Engineering Physics Program Ames Laboratory Iowa State University Ames Iowa 50011-3020 

出 版 物：《Physical Review B》 (物理学评论B辑：凝聚态物质与材料物理学)

年 卷 期：2004年第69卷第6期

页      面：064410-064410页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

主　　题：antiferromagnetics magnetic phase boundaries (including magnetic transitions metamagnetism etc.) magnetization curves hysteresis barkhausen and related effects static properties (order parameter static susceptibility heat capacities critical ex Fc magnetic transitions Magnetic structure Metamagnetism magnetization curve magnetic field Atomic Force Microscopy Barkhausen effect Heat capacity Hysteresis isothermal magnetization Antiferromagnetic ordering 

摘      要：Temperature and magnetic field dependent magnetization and heat capacity of polycrystalline Gd5Ge4 have been measured. In addition to the antiferromagnetic ordering observed at the Néel temperature, TN=128K, there is a cusp at ∼17.5K in the low-field zero-field cooled (zfc) M(T) curves, below which the zfc and field-cooled (fc) magnetic data exhibit irreversibility. The zfc and fc magnetization data show a complex mixture of reversible and irreversible behaviors at fields between ∼10 and ∼18kOe, which is correlated to the magnetic field induced transitions between the antiferromagnetic (AFM) and the ferromagnetic (FM) states. The initial zfc M(H) data below a certain temperature exhibit two transitions: a discontinuous metamagnetic-like transition and a continuous magnetic moment rotation process. The anomalies in the isofield and isothermal magnetization data indicate a complex magnetic structure at low temperatures, e.g., a complex canted AFM structure. In addition, magnetic field or temperature induced AFM↔FM transitions occur under certain conditions. The unusual magnetic behavior is discussed in terms of a possible complex magnetic structure at low temperatures and a martensitic-like structural change induced by the magnetic field