Magnetic phase transitions and electrical switching in Gd5(Sn0.3Ge3.7) induced by magnetic field

Temperature and magnetic field dependences of the magnetization and electrical resistivity of zero-field-cooled (ZFC) Gd5(Sn0.3Ge3.7) with a distinctly layered crystal structure have been studied. The unit cell of Gd5Ge4-based compounds is formed by 2D-like fragments, so-called slabs. Between 4.2 and 17 K, ZFC Gd5(Sn0.3Ge3.7) shows an antiferromagnetic state [AFM(I)], which can be irreversibly transformed by a magnetic field to the ferromagnetic (FM) state. The critical magnetic field required for the irreversible AFM(I)→FM transition in Gd5(Sn0.3Ge3.7) at 4.2 K is 38 kOe, which is 2-fold larger than observed in Ge5Ge4, 19 kOe. Additionally, ZFC Gd5(Sn0.3Ge3.7) above ∼30 K shows another antiferromagnetic state [AFM(II)], which can be reversibly transformed by a magnetic field to the FM state. The difference between AFM(I) and AFM(II) states (phases) in Gd5(Sn0.3Ge3.7) can be attributed to the orientation of Gd magnetic moments, i.e., their orientation perpendicular or parallel to the slabs. In the temperature range of 17 K≤T≤30 K, both AFM(I) and AFM(II) states (phases) may coexist in the alloy and can be irreversibly or reversibly transformed to the FM state. Magnetic phase transitions in Gd5(Sn0.3Ge3.7) are accompanied with reversible or irreversible switching between the low- [AFM(I) and AFM(II)] and high-resistivity (FM) states.