Magnetic properties of the chemically delithiated LixMn2O4 with 0.07 ≤ x ≤ 1

Magnetism for the LixMn2O4 samples with 0.07 <= x <= 1, which are prepared by a chemical reaction in HNO3 solution, is investigated by direct current susceptibility (chi) and muon-spin rotation/relaxation (mu SR) measurements. The effective magnetic moment (mu(eff)) of Mn ions decreases monotonically with decreasing x, indicating that Mn3+ ions with S=2 (t(2g)(3)e(g)(1)) are oxidized to Mn4+ ions with S=3/2 (t(2g)(3)) with decreasing x. On the other hand, as x decreases from 1 to 0.6, the Curie-Weiss temperature (Theta(p)) increases monotonically from similar to -260 to -100 K, and then levels off to -100 K with further decreasing x. This indicates that the antiferromagnetic interaction is dominant in the whole x range. For the x=0.48 sample, the temperature dependence of chi in field-cooling mode clearly deviates from that in zero-field-cooling mode below similar to 63 K (=T-m). Furthermore, the hysteresis loop is observed in the magnetization vs. field curve at 5 K. Since the zero-field mu SR spectrum is well fitted by a strongly damped oscillation function, the Mn moments for the x=0.48 sample are in a highly disordered fashion down to the lowest temperature measured. (C) 2011 Elsevier Inc. All rights reserved.