A versatile X-ray phase retarder for lock-in XMCD measurements.
J Synchrotron Radiat
; 27(Pt 5): 1240-1246, 2020 Sep 01.
Article
em En
| MEDLINE
| ID: mdl-32876599
X-ray magnetic circular dichroism (XMCD) is a technique commonly used to probe magnetic properties of materials with element and orbital selectivity, which requires the use of circularly polarized (CP) X-rays. It is possible to accomplish XMCD experiments with fixed CP and alternating the magnetic field orientation, but most reliable data are obtained when alternating the magnetization orientation and the polarization between right and left helicities. A versatile strategy has been developed to perform XMCD experiments using a hard X-ray quarter-wave plate, at both polychromatic dispersive and conventional monochromatic optics, in combination with synchronous data acquisition. The switching frequency waveform is fed into a lock-in amplifier to detect and amplify the XMCD signal. The results on a reference sample demonstrate an improvement in data quality and acquisition time. The instrumentation successfully generated 98% of CP X-rays switching the beam helicity at 13â
Hz, with the possibility of faster helicity switching once it is installed at the new Brazilian fourth-generation source, SIRIUS.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Synchrotron Radiat
Assunto da revista:
RADIOLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos