Magnetic phase diagram of magnetoelectric LiMnPO4

Abstract

The nature of the spin-flop (SF) transition in the magnetoelectric quasi-2D Heisenberg system LiMnPO 4 is studied in fields applied along the a axis. A refinement of the magnetic structure using neutron diffraction data in the SF phase reveals that the spins reorient from being parallel to the a axis to be nearly along the c axis at magnetic fields between 4 and 4.7 T, depending on temperature. The low-field antiferromagnetic phase boundary is shown to join the spin-flop line tangentially at the so-called bicritical point, where there is a suppression of the ordering temperature. At the bicritical field, we observe an increased intensity of the Lorentz broadened elastic scattering at magnetic Bragg peaks above T N as compared to zero field and 10 T, without an increase in peak width. This suggests an increased density of fluctuations at the bicritical field as compared to zero field.

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

“…For tests of the widths of the elastic lines a vanadium sample (diameter 1 cm, height 1 cm) was used. For a realistic evaluation of cross-talk, inelastic intensity and resolution at low energies, a 300 mg LiMnPO 4 = S 5/2 sample that orders antiferromagnetically was used [27,28]. For generating comprehensive constant energy maps and for tests of spurious signals and resolution effects, a larger MnF 2 = S 5/2 sample ( ≈ m 30 g) was used, exhibiting a simple antiferromagnetic spin wave spectrum with a single branch (2 ions per unit cell) [29,30].…”

“…[27,28] was re-measured using a single 4.5 meV channel and a Be filter between sample and the MultiFLEXX prototype. The results are shown in Fig.…”

Morphology and Agglomeration Control of LiMnPO4 Micro- and Nanocrystals

“…In addition to their applicability for energy storage, the olivine phosphates exhibit antiferromagnetic spin order and a large magnetoelectric effect in the magnetically ordered phase which is of fundamental research interest but may yield to future applications, too. 20 This is highlighted by the recent discovery of unusual ferrotoroidic domains in LiMPO4 with M = Co or Ni which is discussed in terms of future data storage devices. 21 In this work, we investigate the tailored synthesis of dispersed and agglomerated LiMnPO 4 with dimensions between ∼100 nm and several µm aiming at fundamental information which enables tailoring nano-and microscaled material.…”

Magnetization, crystal structure and anisotropic thermal expansion of single-crystal SrEr2O4

“…This interesting observation rules out the above hypothesis of the existence of frozen Er 3+ moments between 200 and 300 K and further supports that there indeed exist AFM couplings in that temperature regime. In addition, small applied magnetic fields (like 500 Oe used in this study) can stabilize such kind of weak AFM couplings before the processes of spin-flop and spin-flip transitions 21,[35][36][37] occurring at higher field strengthes.…”