Spin-glass state of Fe/Cr multilayer structures with ultrathin iron layers

Interfacial disorder and magnetic frustration in epitaxial Fe/Cr/Fe trilayers studied by thermoremanent magnetization

“…We measured magnetization curves for all samples from -50 kOe to +50 kOe, and observed magnetic hysteresis with coercive forces (about 1 Oe for the samples of T s = 300 • C and 30 ∼ 100 Oe for T s = 400 • C) at 300 K for all samples, which indicates that our epitaxially grown Fe/Cr/Fe trilayers are ferromagnetic at least at 300 K. The result suggests that the internal disorder due to the interdiffusion can be almost disregarded in our samples because the transition temperature becomes lower far below room temperature when such a bulk-like frustration occurs [6,7]. Figure 4 shows time dependence of the TRM in each sample in the linear scale (a) and the logarithmic scale (b).…”

“…The direct observation of the slow dynamics is possible by measuring time dependence of the thermoremanent magnetization (TRM). As far as we know, time decay of the TRM has been measured only in a polycrystalline Fe/Cr system [6] or an epitaxial Fe/Cr with considerable interdiffusion [7] in which dominant origin of the frustration is not the interfacial disorder itself but that including substantial internal disorder. In fact, the magnetic transitions in such systems occur well below room temperature due to the bulk-like disorder [6,7].…”

“…As far as we know, time decay of the TRM has been measured only in a polycrystalline Fe/Cr system [6] or an epitaxial Fe/Cr with considerable interdiffusion [7] in which dominant origin of the frustration is not the interfacial disorder itself but that including substantial internal disorder. In fact, the magnetic transitions in such systems occur well below room temperature due to the bulk-like disorder [6,7]. In this study, in order to investigate the relaxation phenomena of Fe/Cr(001) system in which the interfacial disorder is essential, we prepared the epitaxial Fe/Cr/Fe(001) trilayers with various degrees of the interfacial flatness by using the molecular beam epitaxy (MBE) technique and measured the time dependence of the TRM.…”

Magnetisation and remagnetisation peculiarities of Fe/Cr multilayer films caused by instability of Cr layers magnetic structure

“…At C 1 ¼ C 2 fields H z ¼ 0 ( (18) and (19)) that leads to the short oscillation t short ¼ a period vanish (1).…”

“…The agreement of these results with experimental data may serve as indirect evidence of the validity of the model used. In our paper, we discuss two such results: (i) the existence of noncollinear orientations of the iron layer magnetization M Fe in the field H¼0 [16][17][18]; (ii) the unusual behavior of the magnetization curve, which may go beyond the reversal hysteresis loop [19].…”