Non-Magnetic doping effects on magnetic properties of High-Temperature multiferroic compounds YBaCu1-xZnxFeO5 and YBaCuFe1-yGayFeO5

• Non-magnetic impurity effects at different magnetic sites for high-temperature multiferroic compound YBaCuFeO 5 are investigated. • Magnetic susceptibility measurements were performed on polycrystalline samples of YBaCuFe 1-y Ga y O 5 and YBaCu 1-x Zn x FeO 5 . • Cu 2+ and Fe 3+ ions play distinct roles in determining the magnetic properties and transition temperatures. This study examines the effects of non-magnetic impurities at different magnetic sites on the magnetic properties of the ordered oxygen-deficient perovskite YBaCuFeO 5 , which exhibits multiferroic behavior above room temperature. Magnetic susceptibility measurements were performed on polycrystalline samples of YBaCuFe 1-y Ga y O 5 with Ga 3+ (spin S = 0) doping at Fe 3+ ( S = 5/2) sites and YBaCu 1-x Zn x FeO 5 with Zn 2+ ( S = 0) doping at Cu 2+ ( S = 1/2) sites. Magnetic susceptibility (χ)–temperature ( T ) curves for both doped systems below 50 K did not demonstrate Curie-like behavior indicative of a paramagnetic component, suggesting that free-end spins were not induced by long-range interactions in the systems. From the peak temperatures of the χ– T curves, the doping concentration dependence of the magnetic transition temperatures T N1 and T N2 was determined. For YBaCuFe 1-y Ga y O 5 , both T N1 and T N2 decrease linearly with increasing y . In contrast, for YBaCu 1-x Zn x FeO 5 , T N1 decreases while T N2 increases with increasing x , with T N2 reaching a maximum value at 349 K at x = 0.09. Although the atomic arrangement of Cu 2+ and Fe 3+ ions is randomly distributed within (Cu, Fe)O 5 oxygen pyramids, these results indicate that Cu 2+ and Fe 3+ ions play distinct roles in determining the magnetic properties. Based on these experimental findings, a discussion is provided on the physics of non-magnetic impurity effects to different magnetic ions for the high-temperature multiferroic compound YBaCuFeO 5 .