Surface anisotropy and particle size influence on hysteresis loops in La2/3Ca1/3MnO3 nanoparticles: A simulation approach

- The magnetic response of La2/3Ca1/3MnO3 nanoparticles is simulated using the Monte Carlo method.
- A comprehensive study of the size effects on the thermo-magnetic and hysteretic properties of La2/3Ca1/3MnO3 nanoparticles is presented.
- The impact of the surface anisotropy on the size effects present in La2/3Ca1/3MnO3 nanoparticles is studied and presented.
- Special spin configurations including throttled, hedgehog and artichoke are found and displayed for La2/3Ca1/3MnO3 nanoparticles.

Thermal and hysteretic magnetic properties of La2/3Ca1/3MnO3 nanoparticles were studied using Monte Carlo simulations, with emphasis on the influence of anisotropy. In this work, several nanoparticle sizes ranging from 2.32 to 11.58 nm were analyzed and their properties were compared to those of the bulk material. The magnetic behavior of the material was modeled using the three dimensional Heisenberg model with nearest neighbor interactions. Furthermore, both uniaxial and Néel anisotropies were considered for core and surface magnetic sites respectively. Deviations in the critical temperature and coercive field were observed for nanoparticles when compared with those of the bulk material. In addition to these properties, the special spin configurations that arise from the competition between the exchange, anisotropy and external magnetic field were also studied. All these effects are interpreted in terms of the surface properties such as the Néel anisotropy and the decrease in the coordination number.