排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
2.
3.
L. Seetha Lakshmi V Sridharan DV Natarajan V Sankara Sastry T S Radhakrishnan 《Pramana》2002,58(5-6):1019-1026
Mn site is substituted with closed shell ions (Al, Ga, Ti, Zr and a certain combination of Zr and Al) and also with Fe and
Ru ions carrying the magnetic moment (S=5/2 and 2 respectively) at a fixed concentration of 5 at %. Substitution did not change either the crystal symmetry or the
oxygen stoichiometry. All substituents were found to suppress both the metal-insulator and ferromagnetic transition temperatures
(T
p(ρ) and T
C, respectively) to varied extents. Two main contributions identified for the suppression are the lattice disorder arising
due to difference in the ionic radii between the substituent (r
M) and the Mn3+ ion (r
Mn
3+) and in the case of the substituents carrying a magnetic moment, the type of magnetic coupling between the substituent and
that of the neighboring Mn ion. 相似文献
4.
5.
6.
van Buuren LD Szczerba D Alarcon R Boersma DJ van den Brand JF Bulten HJ Ent R Ferro-Luzzi M Harvey M Heimberg P Higinbotham DW Klous S Kolster H Lang J Militsyn BL Nikolenko D Norum BE Passchier I Poolman HR Rachek I Simani MC Six E de Vries H Zhou ZL 《Physical review letters》2002,89(1):012001
We report on measurements of the cross section and provide first data on spin correlation parameters A(TT') and A(TL') in inclusive scattering of longitudinally polarized electrons from nuclear-polarized hydrogen. Polarized electrons were injected into an electron storage ring operated at a beam energy of 720 MeV. Polarized hydrogen was produced by an atomic beam source and injected into an open-ended cylindrical cell, located in the electron storage ring. The four-momentum transfer squared ranged from Q2 = 0.2 GeV(2)/c(2) at the elastic scattering peak to Q2 = 0.11 GeV(2)/c(2) at the Delta(1232) resonance. The data provide a stringent test of pion electroproduction models. 相似文献
7.
Ron G Glister J Lee B Allada K Armstrong W Arrington J Beck A Benmokhtar F Berman BL Boeglin W Brash E Camsonne A Calarco J Chen JP Choi S Chudakov E Coman L Craver B Cusanno F Dumas J Dutta C Feuerbach R Freyberger A Frullani S Garibaldi F Gilman R Hansen O Higinbotham DW Holmstrom T Hyde CE Ibrahim H Ilieva Y de Jager CW Jiang X Jones MK Kang H Kelleher A Khrosinkova E Kuchina E Kumbartzki G LeRose JJ Lindgren R Markowitz P May-Tal Beck S McCullough E Meekins D Meziane M Meziani ZE Michaels R 《Physical review letters》2007,99(20):202002
High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected. 相似文献
8.
Passchier I van Buuren LD Szczerba D Alarcon R Bauer TS Boersma DJ van Den Brand JF Bulten HJ Ent R Ferro-Luzzi M Harvey M Heimberg P Higinbotham DW Klous S Kolster H Lang J Militsyn BL Nikolenko D Nooren GJ Norum BE Poolman HR Rachek I Simani MC Six E de Vries H Wang K Zhou ZL 《Physical review letters》2002,88(10):102302
The spin-momentum correlation parameter A(V)(ed) was measured for the 2H-->(e-->,e'p)n reaction for missing momenta up to 350 MeV/c at Q2 = 0.21 (GeV/c)(2) for quasielastic scattering of polarized electrons from vector-polarized deuterium. The data give detailed information about the deuteron spin structure and are in good agreement with the results of microscopic calculations based on realistic nucleon-nucleon potentials and including various spin-dependent reaction mechanism effects. The experiment reveals in a most direct manner the effects of the D state in the deuteron ground-state wave function and shows the importance of isobar configurations for this reaction. 相似文献
9.
We analyze the amplitude for radiative charged pion photoproduction within the framework of heavy baryon chiral perturbation
theory and discuss the best experimental setup for the extraction of the pion polarizabilities from the differential cross
section.
Correspondence: C.-W. Kao, Department of Physics, Chung Yuan Christian University, Chung-Li 320, Taiwan 相似文献
10.
Wesselmann FR Slifer K Tajima S Aghalaryan A Ahmidouch A Asaturyan R Bloch F Boeglin W Bosted P Carasco C Carlini R Cha J Chen JP Christy ME Cole L Coman L Crabb D Danagoulian S Day D Dunne J Elaasar M Ent R Fenker H Frlez E Gan L Gaskell D Gomez J Hu B Jones MK Jourdan J Keith C Keppel CE Khandaker M Klein A Kramer L Liang Y Lichtenstadt J Lindgren R Mack D McKee P McNulty D Meekins D Mkrtchyan H Nasseripour R Niculescu I Normand K Norum B Pocanic D Prok Y Raue B Reinhold J Roche J Rohe D 《Physical review letters》2007,98(13):132003
We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV相似文献