Manganese monophosphate MnP single crystal deserves attention due to its rich magnetic phase diagram, which is quite different depending on the direction of the applied magnetic field. Generally speaking, it has a Curie temperature around $291\mathrm{K}$ and several other magnetic arrangements at low temperatures (cone-, screw-, fan-, and ferromagnetic-type structures). This richness is due to the strong magnetocrystalline anisotropy. In this sense, the present paper makes a thorough description of the influence of this anisotropy on the magnetocaloric properties of this material. From a fundamental view we could point out, among those several magnetic arrangements, the most stable one. On the other hand, from an applied view, we could show that the magnetic entropy change around room temperature ranges from $-4.7\text{to}-3.2\mathrm{J}∕\mathrm{kg}\mathrm{K}$, when the magnetic field $\left(5\mathrm{T}\right)$ is applied along the easy and hard magnetization directions, respectively. In addition, we have shown that it is also possible to take advantage of the magnetic anisotropy for magnetocaloric applications, i.e., we have found a quite flat magnetic entropy change (with a huge relative cooling power), at a fixed value of magnetic field, only rotating the crystal by 90°.

• Received 8 November 2007

DOI:https://doi.org/10.1103/PhysRevB.77.104439