Mo–Fe antisite defects in Sr2FeMoO6 studied by NMR

NMR study in a half-metallic system, Sr2FeMoO6

“…1. The spectrum shape, which consists of main asymmetric resonance line at about $67 MHz and a low-frequency tail, is quite similar to those reported by several authors [2][3][4][5]. This implies that the hyperfine fields are less affected by the antisite contained, as previously reported [2].…”

“…The spectrum shape, which consists of main asymmetric resonance line at about $67 MHz and a low-frequency tail, is quite similar to those reported by several authors [2][3][4][5]. This implies that the hyperfine fields are less affected by the antisite contained, as previously reported [2]. The main resonance line is assigned as superposition of 95 Mo and 97 Mo lines [2][3][4], where the two isotope lines are indistinguishably close to each other due to the nearly same gyromagnetic constants.…”

“…This implies that the hyperfine fields are less affected by the antisite contained, as previously reported [2]. The main resonance line is assigned as superposition of 95 Mo and 97 Mo lines [2][3][4], where the two isotope lines are indistinguishably close to each other due to the nearly same gyromagnetic constants. In fact, we have confirmed that the main line with H is shifted to higher in frequency at the rate corresponding to the gyromagnetic constants of 95 Mo and 97 Mo, implying a Mo hyperfine field parallel to H. This is consistent with the magnetic structure of SFMO, wherein the smaller magnetic moments at the Mo site (antiparallel to H) and the larger Fe moments (parallel to H) both give rise to respective onsite hyperfine fields with the negative coupling constants [4].…”

“…It implies non-vanishing 4d electron densities with highly polarization, in other words, itinerant down-spin magnetic moments originating from 4d. Several experiments including nuclear magnetic resonance (NMR) [2][3][4][5] have proven the existence of the 4d magnetic moments at the Mo site, which is antiparallel to the Fe moments. In this paper, in order to elucidate the microscopic nature of the 4d electrons showing highly polarized itinerancy, we report Mo-NMR studies in SFMO, which would directly probe the 4d electrons.…”

Ferromagnetic coupling strength and electron-doping effects in double perovskites

“…7 the 95,97 Mo NMR spectra of some samples of the La x Sr 2Àx FeMoO 6 series [12]. Detailed analysis of the spectra revealed that the Mo hyperfine field is mainly due to atomic Mo magnetic moments and no contribution of transferred fields was observed [19]. This is consistent with the absence of s electrons in the conduction band in these oxides [1].…”