The effect of antisite disorder on magnetic and exchange bias properties of Gd-substituted Y 2 CoMnO 6 double perovskite.

Combining experimental investigations and first-principles DFT calculations, we report physical and magnetic properties of Gd doped YCoMnO(YCMO) double perovskite (DP), which are strongly influenced by antisite-disorder(ASD)-driven spin configurations. On Gd doping, Co and Mn ions are present in mixed valence (Co, Co, Mnand Mn) states. Multiple magnetic transitions have been observed: i) paramagnetic to ferromagnetic transition is found to occur at T=95.5 K, ii) antiferromagnetic transition at T=47 K is driven by 3d - 4f polarisation and ASD present in our sample, iii) change in magnetization below T ≤20 K, primarily originating from Gd or- dering, as revealed from our DFT calculations. AC susceptibility measurement confirms the absence of any spin-glass or cluster-glass phases in this material. A significantly large exchange bias (EB) effect (H=1.07 kOe) is found to occur below 47 K due to interfaces of FM and AFM clusters created by antisite-disorder.