Coexistence of sign reversal of both magnetization and exchange bias field in the core-shell type La0.2Ce0.8CrO3 nanoparticles

Abstract

We report an extraordinary coexistence of sign reversal of both magnetization and exchange bias field in the La0.2Ce0.8CrO3 nanoparticles. From the high resolution transmission electron microscopy image, and field dependence of thermoremanent and isothermoremanent magnetization measurements, the nanoparticles are found to be of core-shell nature. The core-shell configuration with an antiferromagnetic core of the Cr3+ and Ce3+ spins and a disordered shell with the uncompensated spins, explains the sign reversal of both magnetization and exchange bias field. The present study shows an excellent way of tuning the sign of both magnetization and exchange bias field in a single magnetic system.

Zero-field cooled exchange bias effect in La Sm1−CrO3 (x=0–0.9) ceramics

“…Below the spin reorientation transition temperature (T SR ), the weak FM moment generates an internal field (H I ) at the R 3 þ site [28]. Due to the paramagnetic effect of magnetic R 3 þ , the antiparallel coupling between R 3 þ and Cr 3 þ sometimes brings about spin reorientation [10][11][12][13][14][15], negative magnetization [16][17][18][19], and EB effects [20][21][22][23]. By changing the magnitude of external magnetic field, tunable magnetic behavior can be obtained.…”

“…Recently, spontaneous magnetic anisotropy induced by spin reorientation causes renewed interests in rare-earth orthochromites [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. The compounds RCrO 3 (R ¼La-Lu, and Y) crystallize in orthorhombic distorted perovskite structure with four formula units per unit cell [27].…”

Anomalous temperature and interfacial‐coupling dependence of exchange bias in antiferromagnetic (core)/ferromagnetic (shell) nanoparticles

“…Recently, the reports on the sign reversal of H E due to the change in temperature in the systems, such as Co (FM)/CuMn (spin glass) bilayers [27], Fe (FM)/Gd (FM) multilayers [28], and the core/shell-type La 0.2 Ce 0.8 CrO 3 nanoparticles [29], have been steadily increasing. Nogués et al [30] studied the FeF 2 /Fe bilayer system and proposed qualitatively that one necessary condition for the occurrence of a positive EB is the AFM interfacial coupling.…”

Sign reversal of magnetization and tunable exchange bias field in NdCr1−xFexO3 (x=0.05–0.2)

“…Substitutions on rare earth site using other rare earth elements and on Cr site using other transition elements give rise to interesting properties like magnetization reversal (MR) and exchange bias (EB) phenomena. Even though MR is known to appear in ferrimagnetic (FIM) compounds [7], recently many other compounds such as Sr 2 YbRuO 6 [8], orthochromites [5,[9][10][11][12][13][14][15][16][17][18][19][20][21], orthoferrites [22][23][24], othovanadates [25,26], molecular magnets [27,28] and intermetallic alloys [29,30] are shown to exhibit such behavior. Exchange bias phenomenon has been studied in heterostructure of bilayer/multilayer thin films of AFM/FM, AFM/FIM (ferrimagnetic), AFM/SG (spin glass), etc.…”