The influence of Cu doping on the charge-ordering of La0.5Ca0.5MnO3

The effect of Cu eloping at Mn site on the magnetic and transport propertie s of the antiferromagnetic charge-ordered (CO) compound La(0.5)Cao(0.5)MnO( 3) has been studied. A slight Cu doping makes the Curie temperature T-C inc rease and the charge-ordered temperature T-CO decrease, while T-C decreases and T-CO increases as the Cu doping level is increased further. Our result s suggest that the Cu doping has twofold effects: destroying the orbital or dering of Mn3+ ions and weakening the role of double exchange between Mn3and Mn4+. This map be the reason that only in the sample with slight doping (x - 0.01) the melting of CO start at an external magnetic field is favore d.