Atomic domain magnetic nanoalloys: interplay between molecular structure and temperature dependent magnetic and dielectric properties in manganese doped tin clusters

Abstract

We present extensive temperature dependent (16-70 K) magnetic and electric molecular beam deflection measurements on neutral manganese doped tin clusters Mn/SnN (N = 9-18). Cluster geometries are identified by comparison of electric deflection profiles and quantum chemical data obtained from DFT calculations. Most clusters adopt endohedral cage structures and all clusters exhibit non-vanishing magnetic dipole moments. In the high temperature regime all species show exclusively high field seeking magnetic response and the magnetic dipole moments are extracted from the shift of the molecular beam. At low nozzle temperatures, some of the clusters show considerably broadened beam profiles due to non-uniform deflection in the magnetic field. The results reflect the influence of the chemical environment on the magnetic properties of the transition metal in atomic domain magnetic nanoalloys. Different ground state spin multiplicities and coupling of rotational and vibrational degrees of freedom with the spin angular momentum of isolated clusters of different size apparently cause these variations of spin orientation. This is discussed by taking electronic and molecular structure data into account.

Stern-Gerlach Experiments on Fe@Sn12: Magnetic Response of a Jahn–Teller Distorted Endohedrally Doped Molecular Cage Cluster

“…The supersonic expansion vastly decreases the translational and rotational temperature of the clusters, but the influence on the vibrational temperature is small. 3,4,17,18 It has been demonstrated by the temperaturedependent superatomic response of Mn@Sn 12 that the vibrational temperature of the clusters is approximately equal to T nozzle with this setup if the clusters are sufficiently close to thermal equilibrium with the nozzle (before the supersonic expansion occurs). 3 The highly collimated molecular beam then passes a magnetic deflection unit with an inhomogeneous magnetic field (two-wire field analogue, 19 0−1.5 T, 0−335 T/ m).…”

“…3,4,17,18 It has been demonstrated by the temperaturedependent superatomic response of Mn@Sn 12 that the vibrational temperature of the clusters is approximately equal to T nozzle with this setup if the clusters are sufficiently close to thermal equilibrium with the nozzle (before the supersonic expansion occurs). 3 The highly collimated molecular beam then passes a magnetic deflection unit with an inhomogeneous magnetic field (two-wire field analogue, 19 0−1.5 T, 0−335 T/ m). The spatial distribution of the clusters in the molecular beam is then measured size selectively without and with applied magnetic field by a scanning slit and recording the cluster intensities by photo ionization time-of-flight mass spectrometry.…”

“…Although the vibrational spectrum of the cluster is not known, we are confident that a significant amount of the ensemble of clusters is rigid at 16 K nozzle temperature, because the temperature-dependent studies on Mn@Sn N showed clearly that vibrationally excited clusters show uniform deflection, that is, vanishing broadening of the beam profile. 3 The width of the beam profile of Fe@Sn 12 is distinctively affected by the inhomogeneous magnetic field at 16 K, indicating that at least a fraction of the cluster ensemble is in the vibrational ground state.…”

“…In our recent work we have estimated the average uncertainty to ±1 μ B , owing especially to the rather low intensity of most species in the mass spectra. 3 As this is not so much a concern with the cluster investigated here (the species TM@Sn 12 , in general, show large abundances), the uncertainty assumed in these measurements is estimated as 0.4 μB, taking twice the standard deviation. Additionally, the value of μ 0 obtained by eq 1 depends on the assumption T vib ≈ T nozzle .…”

A Study of SnnAl Clusters by Density Functional Theory: Comparison with Their Anions and Cations

“…[24][25][26] There are some reports on the doped tin cluster. [27][28][29][30][31][32][33][34][35][36][37][38][39] An interesting example is icosahedral MnSn 12 cluster where Kumar and Kawazoe [27] showed that the doping of a Mn atom could increase the magnetic moment. The atom loss process was also enhanced when a tin atom was substituted by a lead atom in the homoatomic Sn þ 12 cluster.…”