Determination of the effective anisotropy constant of magnetic nanoparticles – Comparison between two approaches

•Estimation of temperature dependence of effective anisotropy constant.•Comparison of two methods: analysis of coercive field and fitting of m-H curves.•Application to two single-core MNP systems.•Good agreement is found if size distribution is included in analysis.•For both nanoparticle system paramagnetic-like contribution was observed.