NMR for magnetite

  • Received : 2018.11.26
  • Accepted : 2018.12.12
  • Published : 2018.12.20


Magnetite is the oldest magnet material known to mankind. It is getting attention again from solid state physics researchers now a days because it is one of the most strongly correlated electron systems. Spin, charge, and orbital orders are interplaying with lattice and involved in the Verwey transition where magnetization, conductivity, and structure changes suddenly. The peculiar ordering states above and below the transition temperature mainly originate from the coexistence of $Fe^{2+}$ and $Fe^{3+}$ ions in the B site of the inverse spinel structure. In particular, the state of the charge and orbital order was the oldest and most intriguing problem. NMR has made significant contribution to the investigation of this question. A. Abragam stated that there is no doubt that NMR is a very powerful tool for the study of ferromagnetic and antiferromagnetic materials. In this mini-review, a short history of NMR investigation of magnetite is presented, providing a support to Abragam's claim.


JGGMB2_2018_v22n4_101_f0001.png 이미지

Figure 1. Resistivity vs. temperature of magnetite. Phase transition is observed around 120 K.2

JGGMB2_2018_v22n4_101_f0002.png 이미지

Figure 2. Variation of the NMR frequency of Fe57 in Fe3O4 with temperature. The frequency at which the most intense echo signal is observed is plotted for the inhomogeneously broadened line from B ion4.

JGGMB2_2018_v22n4_101_f0003.png 이미지

Figure 3. Temperature dependence of the NMR frequency of lines corresponding to Fe on tetrahedral (A) and octahedral (B) sites5.

JGGMB2_2018_v22n4_101_f0004.png 이미지

Figure 4. Anisotropic hyperfine field vs. external field direction for three different orbitals, as the spin direction changes from z to y axis, y to x, and x to back to z axis6.

JGGMB2_2018_v22n4_101_f0005.png 이미지

Figure 5. Orbital ordering structure of B-site Fe ions on (111) plane and adjacent to it7.

JGGMB2_2018_v22n4_101_f0006.png 이미지

Figure 6. Charge density of extra electron (α) of the Fe(3- α)+ ion in the wave function7. The colors are the same as those in Figure 5.


  1. A. Abragam, "Principles of Nuclear Magnetism", p214, Oxford at the claredon press, 1985
  2. E. J. Verwey, Nature 144, 327 (1939)
  3. E. L. Boyd, Bull. Amer. Phys. Soc. Series II 6, 159 (1961)
  4. T. Mizoguchi and M. Inoue, J. Phys. Soc. Jpn. 21, 1310 (1966)
  5. P. Novak, H. Stepankova, J. Englich, J. Kohout, and V. A. M. Brabers, Phys. Rev. B 61, 1256 (2000)
  6. J. Shim, Ph. D. thesis, KAIST, 64 (2008)
  7. M. Mizoguchi, J. Phys. Soc. Jpn. 70, 2333 (2000)
  8. M. Senn, J. Wright, and J. Attfield, Nature 481, 173 (2011)