Electric field effect on exchange interaction in ultrathin Co films with ionic liquids

Abstract

Electric-field modulations of magnetic properties have been extensively studied not only for practical applications but also for fundamental interest. In this study, we investigated the electric field effect on the exchange interaction in ultrathin Co films with ionic liquids. The exchange coupling J was characterized from the direct magnetization measurement as a function of temperature using Pt/ultrathin Co/MgO structures. The trend of the electric field effect on J is in good agreement with that of the theoretical prediction, and a large change in J by applying a gate voltage was observed by forming an electric double layer using ionic liquids.

Manipulation of the RKKY exchange by voltages

“…The discovery of such a system in the late 1980s 16,17 opened the possibility of developing new devices, highlighting the relevance of the control of the exchange coupling, for example by choosing the properties of the Fermi surface of the spacer [18][19][20] . Other realizations of voltage-controlled systems include nuclear spins 21 , magnetic dimers between electrodes 22 , two-dimensional materials [23][24][25][26][27][28] , and ultrathin Co films [29][30][31] . Magnetization can be induced in platinum at metal|dielectric interfaces 32 .…”

Electric-field control of the exchange interactions

“…It is worth noting in addition that despite a short screening length in metals [3] a rather pronounced magneto-electric effect was demonstrated within DFT calculations performed for thin metallic Fe(001), Ni(001), and Co(0001) films [8]. Experimentally, a significant field induced change of the Curie temperature T C was observed for Co ultrathin films embedded into different layered structures [6,25]. The dependence of T C on the electric field strength was attributed to the corresponding modification of the interatomic exchange interactions J ij .…”

“…The control of magnetic properties by applying an electric field is discussed in the literature since many years [1][2][3][4][5][6][7][8][9][10][11][12]. Apart from the well known example of the magneto-crystalline anisotropy (MCA) influenced by an electric field [5,[13][14][15][16], various types of the magnetoelectric (ME) effects have been discussed.…”