Antisite disorder and phase segregation in Mn<sub>2</sub>NiSn
S V Malik, E. T. Dias, A. K. Nigam, K. R. Priolkar
Abstract
Abstract A systematic study of crystal structure, local structure, magnetic and transport properties in quenched and temper annealed Ni <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>−</mml:mo> <mml:mi>x</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> Mn <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo> <mml:mi>x</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> Sn alloys indicate the formation of Mn 3 Sn type structural defects caused by an antisite disorder between Mn and Sn occupying the Y and Z sublattices of X 2 YZ Heusler structure. The antisite disorder is caused by the substitution of Ni by Mn at the X sites. On temper annealing, these defects segregate and phase separate into <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>L</mml:mi> <mml:msub> <mml:mn>2</mml:mn> <mml:mn>1</mml:mn> </mml:msub> </mml:math> Heusler and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>D</mml:mi> <mml:msub> <mml:mn>0</mml:mn> <mml:mrow> <mml:mn>19</mml:mn> </mml:mrow> </mml:msub> </mml:math> Mn 3 Sn type phases.