scholarly journals The proton-pickup reactions as a means to study the spin-polarization and the magnetic moments in 35,37K

2019 ◽  
Vol 14 ◽  
pp. 101
Author(s):  
T. J. Mertzimekis ◽  
P. F. Mantica ◽  
A. D. Davies ◽  
S. N. Liddick ◽  
B. E. Tomlin

Spin polarization in fragmentation reactions has been studied in several nuclei showing mainly that large polarization is produced at the tail of the fragments momentum distribution. Such polarization features are not so well known in pickup reactions, especially in studies of unstable nuclei, such as 35K and 37K. The spin polarization of 35K and 37K produced in single-proton pickup reactions at intermediate energies at the Coupled Cyclotrons at NSCL and the results for the ground-state magnetic moment involving the /3-NMR technique are reported in the present work.

2021 ◽  
Vol 35 (05) ◽  
pp. 2150088
Author(s):  
G. Kasprzak ◽  
J. Rzacki

This paper presents results of density functional theory (DFT) studies on structural, electronic, and magnetic properties of novel Y2FeSi Heusler material characterized by spin polarization at Fermi level of [Formula: see text] and magnetic moment of 1.56 [Formula: see text]. The total magnetic moment of investigated material is dominated by Iron sites, while magnetic moments coming from Yttrium sites are aligned antiparallel to the Iron. Here, we introduced Co and Mn substitutions to alter the magnetic and electronic properties of the studied material. The Heusler alloys are very sensitive to electronic structure changes induced by ionic substitutions, which allowing to specifically modulate their properties. The Co-substitution lowered the total magnetic moment to [Formula: see text][Formula: see text]1.20 [Formula: see text] and Mn caused a rise to [Formula: see text][Formula: see text]1.93 [Formula: see text]. Introduction of Mn resulted in [Formula: see text] spin polarization. We hope that this study will promote further theoretical as well as experimental interest in these types of compounds.


Open Physics ◽  
2014 ◽  
Vol 12 (12) ◽  
Author(s):  
Hakan Yakut ◽  
Emre Tabar ◽  
A. Kuliev ◽  
Ekber Guliyev

AbstractIn this paper the Quasiparticle-Phonon Nuclear Model (QPNM), based on QRPA (Quasiparticle Random Phase Approximation) phonons, has been utilized to investigate spin polarization effects on the groundstate magnetic properties such as intrinsic magnetic moment (g K) and effective spin gyromagnetic factor (g seff.) of odd-mass deformed 165–179Hf isotopes with K > 1/2. Investigations of the spin polarization effects of the even core on the magnetic moments show that the spin gyromagnetic factors (g s) of the nucleons in the nucleus differ noticeably from the corresponding values for free nucleons and that the spin-spin interactions play an important role in the re-normalization of g s factors of the odd-mass 165–179Hf isotopes. In addition, some theoretical predictions are presented for the magnetic moments of 165Hf, 167Hf, and 169Hf, whose ground state magnetic moments haven’t been experimentally determined yet.


2020 ◽  
Vol 15 ◽  
pp. 144
Author(s):  
T. J. Mertzimekis

The neutron-deficient region of the nuclear chart provides unique opportunities to study several important effects near the proton-drip line pertaining to nuclear structure and nuclear astrophysics.The present article focuses on nuclei with isospin Tz=−3/2 in terms of the spin polarization and the ground state magnetic moment. An experiment on measuring the ground state moment pf 35K by employing the β-NMR technique leads to several interesting results that pose challenging questions to theory.


2003 ◽  
Vol 90 (20) ◽  
Author(s):  
D. E. Groh ◽  
P. F. Mantica ◽  
A. E. Stuchbery ◽  
A. Stolz ◽  
T. J. Mertzimekis ◽  
...  

Author(s):  
M. M. Glazov

The transfer of nonequilibrium spin polarization between the electron and nuclear subsystems is studied in detail. Usually, a thermal orientation of nuclei in magnetic field is negligible due to their small magnetic moments, but if electron spins are optically oriented, efficient nuclear spin polarization can occur. The microscopic approach to the dynamical nuclear polarization effect based on the kinetic equation method, along with a phenomenological but very powerful description of dynamical nuclear polarization in terms of the nuclear spin temperature concept is given. In this way, one can account for the interaction between neighbouring nuclei without solving a complex many-body problem. The hyperfine interaction also induces the feedback of polarized nuclei on the electron spin system giving rise to a number of nonlinear effects: bistability of nuclear spin polarization and anomalous Hanle effect, dragging and locking of optical resonances in quantum dots. Theory is illustrated by experimental data on dynamical nuclear polarization.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fridtjof Kielgast ◽  
Ivan Baev ◽  
Torben Beeck ◽  
Federico Pressacco ◽  
Michael Martins

AbstractMass-selected V and Fe monomers, as well as the heterodimer $${\text{Fe}}_1{\text{V}}_1$$ Fe 1 V 1 , were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.


2017 ◽  
Vol 31 (31) ◽  
pp. 1750247
Author(s):  
Qingyu Huo ◽  
Zhenchao Xu ◽  
Linfeng Qu

Both blue and red shifts in the absorption spectrum of Co-doped ZnO have been reported at a similar concentration range of doped Co. Moreover, the sources of magnetism of Co-doped ZnO are controversial. To solve these problems, the geometry optimization and energy of different Co-doped ZnO systems were calculated at the states of electron spin polarization and nonspin polarization by adopting plane-wave ultra-soft pseudopotential technology based on density function theory. At the state of electron nonspin polarization, the total energies increased as the concentration of Co-doped increased. The doped systems also became unstable. The formation energies increased and doping became difficult. Furthermore, the band gaps widened and the absorption spectrum exhibited a blue shift. The band gaps were corrected by local-density approximation + [Formula: see text] at the state of electron spin polarization. The magnetic moments of the doped systems weakened as the concentration of doped Co increased. The magnetic moments were derived from the coupling effects of [Formula: see text]–[Formula: see text]. The band gaps narrowed and the absorption spectrum exhibited a red shift. The inconsistencies of the band gaps and absorption spectrum at the states of electron spin polarization and nonspin polarization were first discovered in this research, and the sources of Co-doped ZnO magnetism were also reinterpreted.


1999 ◽  
Vol 451 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
H. Ogawa ◽  
K. Asahi ◽  
K. Sakai ◽  
A. Yoshimi ◽  
M. Tsuda ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2339 ◽  
Author(s):  
Xiuwen Zhao ◽  
Bin Qiu ◽  
Guichao Hu ◽  
Weiwei Yue ◽  
Junfeng Ren ◽  
...  

The electronic structure and spin polarization properties of pentagonal structure PdSe2 doped with transition metal atoms are studied through first- principles calculations. The theoretical investigations show that the band gap of the PdSe2 monolayer decreases after introducing Cr, Mn, Fe and Co dopants. The projected densities of states show that p-d orbital couplings between the transition metal atoms and PdSe2 generate new spin nondegenerate states near the Fermi level which make the system spin polarized. The calculated magnetic moments, spin density distributions and charge transfer of the systems suggest that the spin polarization in Cr-doped PdSe2 will be the biggest. Our work shows that the properties of PdSe2 can be modified by doping transition metal atoms, which provides opportunity for the applications of PdSe2 in electronics and spintronics.


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