Anomalous magnetic properties of GdCrTiO5 nanoparticles

Abstract

In this report, the structural and magnetic properties of GdCrTiO5 nanoparticles were explored, which were synthesized through the sol-gel technique and subsequently calcined (at 800 °C). X-ray diffraction (XRD) studies revealed the orthorhombic crystal structure of synthesized GdCrTiO5 nanoparticles with space group Pbam. The transmission electron microscopy (TEM) images, with selected area electron diffraction (SAED) pattern, showed the particle size as 38.0 ± 0.4 nm and single crystalline nature of the sample. The temperature dependence of dc magnetization, M(T), was measured for GdCrTiO5 nanoparticles, and different magnetic transitions were confirmed, including the spin reorientation (TSR), Néel temperature (TN) and compensation temperatures (Tcomp1 and Tcomp2) in the material. Irreversibility appeared in field-cool-cooling (FCC), and field-cool-warming (FCW) curves at low temperatures, indicating a ferromagnetic-antiferromagnetic (FM-AFM) transition. Earlier, this FM-AFM transition and TSR, Tcomp was not observed in bulk GdCrTiO5. Both the FM nature and exchange bias (EB) effect are further established from the field-dependent magnetization measurements. Furthermore, a change in isothermal magnetic entropy (−ΔSm) of 22 ± 3 J.kg-1.K-1 is found below 10 K, for a 7 T difference in the field. The obtained magnetic properties in this report are discussed in terms of exchange frustration originating from the competing interactions of the magnetic sublattices of the Cr3+ and Gd3+ in the GdCrTiO5 nanoparticles.