Weak ferromagnetism and internal magnetoelectric effect in LiFeP${}_2$O${}_7$

Abstract

The magnetic, thermodynamic, and pyroelectric properties of LiFeP${}_2$O${}_7$ single crystals are investigated with emphasis on the magnetoelectric interaction of the electrical polarization with the magnetic order parameter. The magnetic order below T${}_N\simeq$ 27 K is found to be a canted antiferromagnet with a weak ferromagnetic component along the $b-$axis. A sharp peak of the pyroelectric current at T${}_N$ proves the strong internal magnetoelectric interaction resulting in a sizable polarization decrease at the onset of magnetic order. The magnetoelectric effect in external magnetic fields combines a linear and a quadratic field dependence below T${}_N$. Thermal expansion data show a large uniaxial magnetoelastic response and prove the existence of strong spin lattice coupling. LiFeP${}_2$O${}_7$ is a polar compound with a strong interaction of the magnetic order parameter with the electric polarization and the lattice.

8 pages, 9 figures, to be published in Phys. Rev. B

References in corpus (1)

• Magnetically driven ferroelectric order in Ni${}_3$V${}_2$O${}_8$