Widely-sweeping magnetic field–temperature phase diagrams for skyrmion-hosting centrosymmetric tetragonal magnets

Uniaxial Distortion Effect on Magnetic Skyrmion Crystals in a Frustrated Triangular-Lattice System

“…0 induce the instability toward the S-SkX, which has been also found in similar tetragonal magnets [52][53][54].…”

“…Such a relation can lead to the instability toward the S-SkX when the interaction at Q 7 and Q 8 , i.e., J 3 is comparable to that at Q 1 and Q 2 , J 1 [52][53][54]. On the other hand, by combining…”

Zero-Field Skyrmion, Meron, and Vortex Crystals in Centrosymmetric Hexagonal Magnets

“…Microscopically, this Hamiltonian in Eq. ( 2) is derived as an effective spin model of the Kondo lattice model in the weak-coupling regime, where the bare susceptibility of itinerant electrons shows maxima at Q 1 -Q 3 [64,65]; the first term corresponds to the lowest contribution in the perturbation expansion, i.e., Ruderman-Kittel-Kasuya-Yosida interaction [66][67][68], and the second term corresponds to the second-lowest contribution, the latter of which tends to induce various multiple-Q instabilities when its sign is positive [64,69,70], such as the double-Q SkX found in GdRu 2 Si 2 [19,21] and triple-Q vortex crystal in Y 3 Co 8 Sn 4 [71]. We set J as the energy unit of the model Hamiltonian H and treat K > 0 as the phenomenological parameter.…”

“…A magnetic skyrmion crystal (SkX) with nontrivial topological properties has been extensively studied since its direct experimental observation in 2009 [1,2]. Although it was originally discovered in noncentrosymmetric magnets [1][2][3][4], where the competition between the ferromagnetic exchange interaction and the Dzyaloshinskii-Moriya (DM) interaction [5,6] plays an important role [7][8][9][10], its appearance in centrosymmetric magnets has been clarified through the observations for various bulk materials, such as Gd 2 PdSi 3 [11][12][13][14], Gd 3 Ru 4 Al 12 [15,16], GdRu 2 Si 2 [17][18][19][20][21][22] and EuAl 4 [23][24][25][26]. Simultaneously, a variety of SkXs without relying on the DM interaction have been theoretically studied for various lattice structures [27], such as square [28][29][30][31], triangular [32][33][34][35][36][37], and cubic lattices [38].…”

Rectangular and square skyrmion crystals on a centrosymmetric square lattice with easy-axis anisotropy

“…Meanwhile, it has not been clarified the possibility of the SkXs under the in-plane field on a centrosymmetric square lattice, where the effect of geometrical frustration does not appear. Although the * hayami@phys.sci.hokudai.ac.jp emergence of the SkXs on such a square lattice in the out-of-plane magnetic field has been shown by the theoretical model calculations [31][32][33][34] and experiments in GdRu 2 Si 2 [15,[35][36][37][38][39] and EuAl 4 [40][41][42][43], its stabilization condition under the in-plane magnetic field has been unclear yet.…”