Muon Spin Relaxation Study on Sr2-xLaxCoNbO6 (x = 0.2)

Sr2CoNbO6 belongs to the family of double perovskites which are well known for their diverse physical properties. In this material magnetism arises due to a combination of low spin (LS, Co3+, S = 0) and high spin (HS, Co4+, S = 5/2) states of cobalt leading to an antiferromagnetic and/or spin freezing type transition below 20 K. A partial substitution of Sr by La in Sr2-xLaxCoNbO6 leads to a dominance of high spin state of Co for x ≥ 0.2. Sr1.8La0.2CoNbO6 exhibits an AFM ordering below 11 K. Because of high sensitivity of muons to extremely small magnetic field it would be of interest to investigate the magnetic ordering in these compounds using muon spin relaxation technique. We therefore propose to carry out µSR study on Sr1.8La0.2CoNbO6 using the EMU/MUSR spectrometer.