@article { ISI:000264644800018, title = {Ferromagnetic to spin glass cross over in (La,Tb)(2/3)Ca1/3MnO3}, journal = {Solid State Sciences}, volume = {11}, number = {3}, year = {2009}, month = {MAR}, pages = {714-718}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

In the series La2/3-xTbxCa1/3MnO3, it is known that the compositions are ferromagnetic for smaller values of x and show spin glass characteristics at larger values of x. Our studies on the magnetic properties of various compositions in the La2/3-xTbxCa1/3MnO3 series show that the cross over from ferromagnetic to spin glass region takes place above x approximate to 1/8. Also, a low temperature anomaly at 30 K, observed in the ac susceptibility curves, disappears for compositions above this critical value of x. A mixed phase region coexists in the narrow compositional range 0.1 \<= x \<= 0.125, indicating that the ferromagnetic to spin glass cross over is not abrupt. (C) 2008 Elsevier Masson SAS. All rights reserved.

}, keywords = {Ferromagnetism, Magnetic clusters, Manganites, perovskite, Spin glass}, issn = {1293-2558}, doi = {10.1016/j.solidstatesciences.2008.10.002}, author = {Sankar, C. Raj and Vijayanand, S. and Joy, Pattayil Alias} } @article { ISI:000346168600001, title = {Modification of crystal anisotropy and enhancement of magnetic moment of Co-doped SnO2 thin films annealed under magnetic field}, journal = {Nanoscale Research Letters}, volume = {9}, year = {2014}, month = {NOV}, pages = {635}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Co-doped SnO2 thin films were grown by sputtering technique on SiO2/Si(001) substrates at room temperature, and then, thermal treatments with and without an applied magnetic field (H-TT) were performed in vacuum at 600 degrees C for 20 min. H-TT was applied parallel and perpendicular to the substrate surface. Magnetic M(H) measurements reveal the coexistence of a strong antiferromagnetic (AFM) signal and a ferromagnetic (FM) component. The AFM component has a N,el temperature higher than room temperature, the spin axis lies parallel to the substrate surface, and the highest magnetic moment m =7 mu(B)/Co at. is obtained when H-TT is applied parallel to the substrate surface. Our results show an enhancement of FM moment per Co+2 from 0.06 to 0.42 mu(B)/Co at. for the sample on which H-TT was applied perpendicular to the surface. The FM order is attributed to the coupling of Co+2 ions through electrons trapped at the site of oxygen vacancies, as described by the bound magnetic polaron model. Our results suggest that FM order is aligned along [101] direction of Co-doped SnO2 nanocrystals, which is proposed to be the easy magnetization axis.

}, keywords = {Antiferromagnetism, Crystal anisotropy, Diluted magnetic oxide, Ferromagnetism, Magnetic anisotropy, Magnetic moment, Spin axis, thin film}, issn = {1556-276X}, doi = {10.1186/1556-276X-9-635}, author = {Loya-Mancilla, Sagrario M. and Poddar, Pankaj and Das, Raja and Ponce, Hilda E. Esparza and Templeton-Olivares, Ivan L. and Solis-Canto, Oscar O. and Ornelas-Gutierrez, Carlos E. and Espinosa-Magaa, Francisco and Olive-Mendez, Sion F.} } @article {47994, title = {Controlled exchange bias behavior of manganese nanoparticles}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {559}, year = {2022}, month = {OCT}, pages = {169504}, type = {Article}, abstract = {

Mn(0) colloids were synthesized by solvated metal atom dispersion approach utilizing hexadecylamine, toluene, and THF as coordinating ligands. Mn-toluene and Mn-THF nanoparticles were found to be highly pyrophoric in nature and demand careful handling whereas, Mn-HDA nanoparticles undergo slow oxidation. TEM micrographs revealed formation of nanoparticles between 3 and 6 nm. Magnetic studies of these three samples displayed shift in the field-cooled M-H hysteresis loop which has been attributed to exchange bias behavior. The exchange bias field, HE measured at 5 K varies with change in coordinating ligands around the Mn center which are 1217 Oe, 4408 Oe and, 6350 Oe for Mn-HDA, Mn-toluene and Mn-THF nanoparticles, respectively. The large exchange bias field has been attributed to the presence of uncompensated antiferromagnetic surface spins and the exchange interactions at the nanoparticle surface due to surface oxidation.

}, keywords = {Antiferromagnetism, exchange bias, Ferromagnetism, Manganese nanoparticles, Uncompensated spins}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2022.169504}, author = {Tiwari, Garima and Vinod, C. Prabhakaran and Jagirdar, Balaji R.} }