Scaling study and thermodynamic properties of the cubic helimagnet FeGe

Wilhelm, H.; Leonov, A. O.; Rößler, U.; Philipp, B.; Hardy, F.; Meingast, C.; Gruner, Markus E.; Schnelle, Walter; Schmidt, Marcus; Baenitz, M.

doi:10.1103/physrevb.94.144424

Cited by 39 publications

(40 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using high sensitivity Hall Effect measurements in FeGe crystals, we observe a skyrmion THE of amplitude +5 n .cm at 276 K (3°C). This THE coincides with the skyrmion lattice phase identified by small angle neutron scattering 42 , and its amplitude is as large as the THE observed in MnSi at 29 K. Adjacent to the skyrmion phase, we also observe the signature of a magnetic phase that is not present in the prototypical skyrmion compound MnSi, and merges into the inhomogeneous chiral spin state 51 . Finally, comparing THE in MnSi and FeGe we emphasise the quantitative and qualitative failings of the formula that is generally used to estimate the skyrmion THE.…”

Section: Introductionsupporting

confidence: 81%

Skyrmion Lattice Topological Hall Effect near Room Temperature

Leroux

Stolt

Jin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

Magnetic skyrmions are stable nanosized spin structures that can be displaced at low electrical current densities. Because of these properties, they have been proposed as building blocks of future electronic devices with unprecedentedly high information density and low energy consumption. The electrical detection of an ordered skyrmion lattice via the Topological Hall Effect (THE) in a bulk crystal, has so far been demonstrated only at cryogenic temperatures in the MnSi family of compounds. Here, we report the observation of a skyrmion lattice Topological Hall Effect near room temperature (276 K) in a mesoscopic lamella carved from a bulk crystal of FeGe. This region coincides with the skyrmion lattice location revealed by neutron scattering. We provide clear evidence of a re-entrant helicoid magnetic phase adjacent to the skyrmion phase, and discuss the large THE amplitude (5 nΩ.cm) in view of the ordinary Hall Effect.

show abstract

Section: Introductionsupporting

confidence: 81%

Skyrmion Lattice Topological Hall Effect near Room Temperature

Leroux

Stolt

Jin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

show abstract

“…During the last years, the precursor states of noncentrosymmetric ferromagnets have been investigated experimentally and theoretically [14][15][16][17][18][19][20][21][22][23]. Particularly, the recent observations in bulk cubic helimagnets MnSi [18] and FeGe [16][17][18] are consistent with the crossover effects of skyrmionic states theoretically described in [9][10][11] and earlier reported in a cubic helimagnet FeGe [10,11].…”

Section: Introductionsupporting

confidence: 74%

Crossover of skyrmion and helical modulations in noncentrosymmetric ferromagnets

Leonov

Bogdanov

2018

New J. Phys.

View full text Add to dashboard Cite

The coupling between angular (twisting) and longitudinal modulations arising near the ordering temperature of noncentrosymmetric ferromagnets strongly influences the structure of skyrmion states and their evolution in an applied magnetic field. In the precursor states of cubic helimagnets, a continuous transformation of skyrmion lattices into the saturated state is replaced by the first-order processes accompanied by the formation of multidomain states. Recently the effects imposed by dominant longitudinal modulations have been reported in bulk MnSi and FeGe. Similar phenomena can be observed in the precursor regions of cubic helimagnet epilayers and in easy-plane chiral ferromagnets (e.g. in the hexagonal helimagnet CrNb 3 S 6 ).

show abstract

“…Fisher and Langer [59] showed that in the case of short-range interactions, the derivative of the resistivity dρ xx /dT should vary as the magnetic specific heat, which has been seen to be the case in MnSi [60,61]. While FeGe shows a conventional cusp in the specific heat [62], there is no corresponding peak in dρ xx /dT here or in previous work on thin films [32,33]. An alternative theoretical approach is to look at the long-range interaction contribution, which has been used to describe the resistivity anomalies found in periodic magnetic structures, with spin-spiral rare-earth systems given as an example [63].…”

Section: Resistivity and Magnetoresistancementioning

confidence: 96%

Helical magnetic structure and the anomalous and topological Hall effects in epitaxial B20 Fe1−yCoyGe films

et al. 2018

View full text Add to dashboard Cite

Epitaxial films of the B20-structure compound Fe 1−y Co y Ge were grown by molecular beam epitaxy on Si (111) substrates. The magnetization varied smoothly from the bulklike values of one Bohr magneton per Fe atom for FeGe to zero for nonmagnetic CoGe. The chiral lattice structure leads to a Dzyaloshinskii-Moriya interaction (DMI), and the films' helical magnetic ground state was confirmed using polarized neutron reflectometry measurements. The pitch of the spin helix, measured by this method, varies with Co content y and diverges at y ∼ 0.45. This indicates a zero crossing of the DMI, which we reproduced in calculations using first-principles methods. We also measured the longitudinal and Hall resistivity of our films as a function of magnetic field, temperature, and Co content y. The Hall resistivity is expected to contain contributions from the ordinary, anomalous, and topological Hall effects. Both the anomalous and topological Hall resistivities show peaks around y ∼ 0.5. Our first-principles calculations show a peak in the topological Hall constant at this value of y, related to the strong spin polarization predicted for intermediate values of y. Our calculations predict half-metallicity for y = 0.6, consistent with the experimentally observed linear magnetoresistance at this composition, and potentially related to the other unusual transport properties for intermediate value of y. While it is possible to reconcile theory with experiment for the various Hall effects for FeGe, the large topological Hall resistivities for y ∼ 0.5 are much larger than expected when the very small emergent fields associated with the divergence in the DMI are taken into account.

show abstract

Scaling study and thermodynamic properties of the cubic helimagnet FeGe

Cited by 39 publications

References 57 publications

Skyrmion Lattice Topological Hall Effect near Room Temperature

Skyrmion Lattice Topological Hall Effect near Room Temperature

Crossover of skyrmion and helical modulations in noncentrosymmetric ferromagnets

Helical magnetic structure and the anomalous and topological Hall effects in epitaxial B20 Fe1−yCoyGe films

Contact Info

Product

Resources

About