Anomalous Nernst effect in Ir22Mn78/Co20Fe60B20/MgO layers with perpendicular magnetic anisotropy

Abstract

The anomalous Nernst effect in a perpendicularly magnetized Ir22Mn78/Co20Fe60B20/MgO thin film is measured using well-defined in-plane temperature gradients. The anomalous Nernst coefficient reaches 1.8 μV/K at room temperature, which is almost 50 times larger than that of a Ta/Co20Fe60B20/MgO thin film with perpendicular magnetic anisotropy. The anomalous Nernst and anomalous Hall results in different sample structures revealing that the large Nernst coefficient of the Ir22Mn78/Co20Fe60B20/MgO thin film is related to the interface between CoFeB and IrMn.

Large magnetothermopower and anomalous Nernst effect in HfTe5

“…Below the transition temperature T p , the Nernst effect presents a large steplike field dependence [ Fig. 3(c)], the sharpness of which resembles the anomalous Nernst effect (ANE) of ferromagnetic thin films [42]. The ANE responses observed in ferromagnets are usually quite sharp because the field range over which the magnetization switches is narrow.…”

Spin‐Dependent Thermoelectric Transport in Cobalt‐Based Heusler Alloys

“…There were not only comparisons of multiple experimental methods, but also the discovery of new physics and ANE of large magnitudes. [20,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] The improved basic understanding of ANE has made it possible to continuously find materials, including the recently discovered Weyl magnets, with large anomalous Nernst coefficients. For example, due to the important contribution of the Berry phase to the transport properties, a large ANE was measured in antiferromagnet Mn 3 Sn, [43] in which the net magnetization is vanishingly small.…”

“…In fact, since a small temperature difference of only 0.001 K could induce a large temperature gradient of 1000 K cm −1 on a film approximately 10-nm-thick, the difference between anomalous Nernst coefficients measured by different groups in the same material can be large. [13,29] This problem is avoided in studies of perpendicularly magnetized films, [20,30,35,36,94] where one can apply an in-plane temperature gradient which can be characterized easily either by an infrared thermal camera [20,30,94] or thermocouples [35,36] (Figure 7e). On-chip thermometer which can obtain the temperature difference along the sample surface is an ideal technique.…”

“…[1] In this DOI: 10.1002/andp.201900456 review we are concerned with the interaction between spin currents and heat currents, which is now widely known as spin caloritronics. [2][3][4][5][6] The interplay between spin and thermoelectric effects [7][8][9][10][11][12][13][14] has drawn significant interest in both theoretical [15][16][17][18][19] and experimental [20][21][22][23] studies.…”

“…Until now, ANE has been well investigated in many different materials, including the conventional ferromagnetic materials, [25][26][27][28][29][30][31] oxides Fe 3 O 4 [32] and SrRuO 3 crystals, [33] half-metallic ferromagnet (FM) La 2∕3 Sr 1∕3 MnO 3 thin films, [34] rare-earth alloys, [35] multilayered [Pt/Co] n , [36] spin valves, [37] ferromagnetic semiconductors, [38] Weyl/Dirac semimetals, [39][40][41] and antiferromagnetic materials. [20,42,43] The ANE as a phenomenon was well known long before the era of condensed matter physics; however, it is still not fully understood. For example, how the ANE can be tuned by doping, the determinants of the anomalous Nernst coefficient in a given material and the interplay mechanisms between FM and nonmagnetic metal (NM) layers in heterostructures are yet to be revealed.…”