Magnetic and magnetocaloric properties in GdFeTiO5 and GdMnTeO6

Abstract

We report the magnetic and magnetocaloric properties of two Gd-based compounds. First, for the orthorhombic lattice compound GdFeTiO5, no signature of long-range magnetic ordering is observed down to 2 K. The maximum magnetic entropy change (−ΔSMmax) is derived to be 18.9 J kg−1 K−1 at 3 K for 0–3 T and 33.6 J kg−1 K−1at 5 K for 0–7 T, respectively, which is attributed to the rotation of spins of weakly ferromagnetically coupled Gd3+/Fe3+ ions toward the external magnetic field. Second, a new honeycomb layered tellurate GdMnTeO6 is synthesized. The compound crystallizes in a trigonal structure with space group P-31c and is long-range antiferromagnetically ordered at TN = 7.0 K. The value of −ΔSMmax at TN is about 14.8 J kg−1 K−1 for 0–3 T and 29.8 J kg−1 K−1 for 0–7 T, respectively, which is associated with field-induced antiferromagnetic to ferromagnetic transition. Thus, with the large value of −ΔSMmax and the absence of thermal and field hysteresis, both Gd compounds are candidates for low-temperature magnetocaloric materials. In relative to GdFeTiO5, the reduction of MCE in GdMnTeO6 might be associated with antiferromagnetic order.