Evolution of structural and magnetic properties of Ti doped Sr2IrO4: a novel magnetic insulator

1st International Conference on Advanced Engineering Functional Materials

Bhatti, Imtiaz Noor^1 ; Pramanik, A.K.^1

School of Physical Sciences, Jawaharlal Nehru University, New Delhi

110067, India^1

关键词: Crystal field effects;    Effective magnetic moments;    Ferromagnetic character;    Insulator;    Remnant magnetization;    Spin-orbit couplings;    Spin-orbital interactions;    Structural and magnetic properties;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/410/1/012010/pdf
DOI  :  10.1088/1757-899X/410/1/012010

来源: IOP

【 摘 要 】

5d transition metal oxides (TMOs) recently caught attention of researchers because of potential to show exotic phenomenon. Crystal field effect (CFE), spin-orbital interaction (SOI) and onsite Coulomb interaction (U) in 5d oxides are on comparable scale and their interplay among themselves setting new balance of energies and drive exotic physics in these materials. Among several 5d oxides iridates are extensively studied, where Sr2IrO4 is prototype of novel physics and stabilize in Jeff = 1/2; ground state. The Sr2IrO4 is first member of Rudellson-Popper series Srn+1IrnO3n+1 with n = 1 and crystallize in reduced tetragonal structure and adopt 141/acd space group. The physical properties of Sr2IrO4 are influenced by this reduced symmetry due to rotation of IrO6 octahedral. The magnetic ground state in Sr2IrO4 is canted type antiferromagnetic (AFM), it's this canted spin structure which gives ferromagnetic character to this material with ordering temperature around 225 K to this material. The spin canting is rendered by Dzyaloshinskii-Moriyam anti-symmetric interaction driven by SOI and rotated IrO6 octahedra. We endeavour to perturb the interactions viz. SOI and U in Sr2IrO4 by substituting Ti4+ (3d0 S = 0) for Ir4+ (5d5 Jeff = 1/2). We have studied the effect of Ti doping on structural and magnetic properties. We observe evolution in unit cell lattice parameters, in the meantime Ir-O-Ir bond angle also increases which reduces octahedral rotation (θOct). Further, our magnetization study shows decrease in transition temperature (TC), increase in effective magnetic moment and doping influence the coercively and remnant magnetization. Thus we observe Ti doping prominently effect the structural and magnetic properties in Sr2IrO4. The results presented here provide insight into the effect of Ti doping on structure and magnetic phase in strong spin-orbit coupled Sr2IrO4.