Magnetic Ordering and Magnetocaloric Effect of Gdal2si2, Gd3al2 And Gd3al0.8ga1.2

The polycrystalline La2O2S-type GdAl2Si2, Zr3Al2-type Gd3Al2 and Gd3Al1.9Si0.1 (space group P42/mnm, N 136, tP20), Gd3Ga2-type Gd3Al0.8Ga1.2, Gd3Al1.6-1.05Si0.4-0.95, Gd3Al1.35-1.25Ge0.65-0.75, Gd3Ga1.4-1.2Si0.6-0.8 and Gd3Ga1.5-1.2Ge0.5-0.8 are prepared by arc melting with following annealing. GdAl2Si2 shows an antiferromagnetic ordering below TN = 22 K with a metamagnetic transformation in a field of ~15 kOe. Gd3Al2 demonstrates ferrimagnetic ordering at TC = 274 K and possible field induced transformation of magnetic ordering (Tm) around 46 K above 25 kOe. In spite of similar crsystal structure, Gd3Al0.8Ga1.2 exhibits a field-sensitive antiferromagnetic ordering below TN = 60 K, with a metamagnetic transformation of magnetic ordering above 42 kOe. In a field change of 50 kOe, the magnetic ordering of GdAl2Si2 and Gd3Al2 is followed via magnetic entropy change of -10.0 J/kg·K and -5.65 J/kg·K, respectively. Gd3Al0.8Ga1.2 shows magnetic entropy change of -1.83 J/kg·K at 52 K in a field change of 90 kOe, only.