Advanced Topics on Condensed Matter Physics
Department of Physics, NCU
Inverted magnetic hysteresis from spatial dilution in Nix-In100-x nanocomposites
Speaker
Ms. Erdembayalag Batsaikhan
Magnetic Superconductor Laboratory
Department of Physics, National Central University
Date 2016/10/6 (Thur)
Time: 14.00
Place: S4-625
In a usual ferromagnetism, a magnetic hysteresis loop is counterclockwise revolving, resulting in positive remanence magnetization Mr and coercivity Hc when an applied magnetic field decreases to zero from a high field. Interestingly, a clockwise hysteresis loop with negative Mr at low fields has been reported in several inhomogeneous magnetic systems when the applied field is still positive. However, studies on the inverted hysteresis observed in magnetically homogeneous nanosized system have been limited. We report on the observation of the inverted magnetic hysteresis in loosely packed Ni-In nanoparticle assemblies. Remanence magnetization of the Ni nanoparticles decreases from positive to negative values when In nanoparticles are introduced into the vicinity of Ni nanoparticles. The Mr shows a significant upturn at a critical Ni composition and further tends to decrease to zero. We assume that the occurrence of inverted hysteresis in the present study is attributed to the collective nature of ferromagnetic Ni NPs, together with the Ni-Ni inter-particle interactions.