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technical paper
Magnetic phase transitions and magnetocaloric effect in DyCrTiO5 nanoparticles
Rare-earth (R) compounds of the form RCrTiO5, crystallizing in an orthorhombic structure with space group Pbam, belongs to the multiferroic family that are currently of interest as these can find applications in spintronic and memory devices. Recently, there were limited reports on the RCrTiO5 materials in their bulk form 1-4. Das et al. 1 investigated the magnetic ground state of the DyCrTiO5 in a bulk sample through dc magnetization and showed the ferromagnetic nature of the material, as well as spin reorientation at low temperatures because of the interaction between Dy3+ and Cr3+. However, there are currently limited reports in the literature on DyCrTiO5 in its nano form, probing dimensionality effects 5. Therefore, the present work highlights the magnetic transitions of the DyCrTiO5 nanoparticles and their magnetocaloric behavior. The nanoparticles were synthesized through a cost-effective sol-gel technique and subsequently calcined at 800 C. The orthorhombic structure of the material with lattice parameters, a, b, c of 7.3158(7), 8.6431(9), 5.8390(8) Å, respectively, is established from the x-ray diffraction (XRD) pattern. The particle size obtained from transmission electron microscopy (TEM) is 43 ± 2 nm. The Néel temperature has obtained from the magnetization as a function of temperature (M(T)) measurement, as TN = 146 ± 1 K (Fig. 1). In addition, spin reorientation is observed at a temperature, TSR = 51 ± 1 K (Fig. 1). A loop appeared in field-cool-cooling (FCC) and field-cool-warming (FCW) M(T) curves at low temperatures, not previously observed for the sample in bulk form, indicating a ferromagnetic-antiferromagnetic (FM-AFM) transition 5. The FM nature, with exchange bias effect, is further confirmed for the sample from field-dependent magnetization measurements. Additionally, a change in isothermal magnetic entropy (-ΔSm) of 6.6 ± 0.3 J.kg-1.K-1 is found at a 6 T difference in the field. The observed magnetic behavior of DyCrTiO5 nanoparticles is discussed in terms of the competing interactions of Cr3+ and Dy3+, respectively.