Magnetic Property and Charge Ordering Phase in Pr_(0.4)Ca_(0.6)Mn_(1-x)Cr_xO_3

Pr0. 4Ca0. 6Mn1-xCrxO3(x = 0. 00,0. 04,0. 06,0. 08,0. 10,0. 12) were prepared by the solid-state reaction method. The influences of Cr3 +substitution for Mn3 +on magnetic property and charge ordering phase of Pr0. 4Ca0. 6MnO3 were studied through X-ray diffraction(XRD) patterns,magnetization-temperature(M-T) curves,electron spin resonance(ESR) patterns,normalized intensity – temperature(I/I300 – T) curves and peak-peak band width-temperature(△Bpp-T) curves according to ESR. The results indicate that,for the original material Pr0. 4Ca0. 6MnO3,charge ordering transition temperature Tcois equal to 267 K,long-range antiferromagnetic order exists in the temperature range 205 K ~ 62 K,and a little ferromagnetic component appears in the antiferromagnetic background below 50 K; for the sample with x =0. 06,charge ordering phase has basically been destroyed,paramagnetism-antiferromagnetism transition occurs with temperature decreasing,and ferromagnetic component exists in the antiferromagnetic background; for the sample with x = 0. 10,charge ordering phase has completely been destroyed,antiferromagnetic and ferromagnetic mixed phase exists below 250 K,and ferromagnetic component increases. Charge ordering phase has been destroyed because of the substitution of magnetic Cr3 +with the same electronic structure(t32ge00) as Mn4 +for Mn3 +,the mechanism is that Cr3 +substitution for Mn3 + causes the spin order to change and then causes the charge order to be destroyed,and this indicates that strong coupling interaction between the spin order and the charge order exists in CE-type antiferromagnetic system.