Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds
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The Ohio State University / OhioLINK
2014
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1408984221 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu14089842212021-08-03T06:27:12Z Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds Peters, Brian Physics Materials Science Heusler Co2FeSi Co2FeAlSi Co2FeAl Spintronics thin films XRD point contact andreev reflection PCAR spin NMR nuclear magnetic resonance Co2FeAlxSi1-x Co2FeAl1-xSix condensed matter physics <p>Co<sub>2</sub>FeSi is one of the most studied half metallic Heusler compounds with the potential for room temperature magnetoelectronic applications on account of it having the highest know Curie temperature (above 1000 K) among potential ferromagnets. Despite its promise, researchers have had mixed results in growing films of sufficiently high quality to realize its full potential. By identifying and controlling critical factors that complicate attempts to grow high quality films of Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> , we have overcome many obstacles including off-stoichiometry, impurity phase formation and disorder. All of which must be addressed in order to achieve half-metallicity. This dissertation reports an in-depth investigation that addresses several critical issues about the deposition of Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> epitaxial films using off-axis ultrahigh vacuum sputtering.</p> <p>We have discovered that, the choice of a lattice matched substrate plays a dominant role in the stoichiometry and phase formation of these films. Film disorder was categorized by nuclear magnetic resonance (NMR) as well as X-ray diffraction (XRD) to identify both short and long range order in the crystal. X-ray diffractometry shows the films to be epitaxial, pure-phase and well ordered. Magnetic characterization was done via vibrating sample magnetometry (VSM) and superconducting quantum interference device (SQUID) magnetometry. We observed a saturation magnetization of 5.5-6.0 mB per formula unit at T = 300 K, roughly in line with expectation for the film stoichiometry and ordering level and consistent with the Slater Pauling rules. X-ray diffraction and nuclear magnetic resonance gave high values (~74-87%) for the level of L2<sub>1</sub> and B2 ordering in these films. Point Contact Andreev reflections were also performed on these films to evaluate the level of spin polarization in these materials.</p> <p>The Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> films grown exhibit a combination of several desired properties and should be a suitable material candidate for spintronics applications.</p> 2014 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1408984221 http://rave.ohiolink.edu/etdc/view?acc_num=osu1408984221 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Physics Materials Science Heusler Co2FeSi Co2FeAlSi Co2FeAl Spintronics thin films XRD point contact andreev reflection PCAR spin NMR nuclear magnetic resonance Co2FeAlxSi1-x Co2FeAl1-xSix condensed matter physics |
| spellingShingle |
Physics Materials Science Heusler Co2FeSi Co2FeAlSi Co2FeAl Spintronics thin films XRD point contact andreev reflection PCAR spin NMR nuclear magnetic resonance Co2FeAlxSi1-x Co2FeAl1-xSix condensed matter physics Peters, Brian Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| author |
Peters, Brian |
| author_facet |
Peters, Brian |
| author_sort |
Peters, Brian |
| title |
Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| title_short |
Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| title_full |
Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| title_fullStr |
Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| title_full_unstemmed |
Tuning the structural, magnetic and transport properties of full Heusler Co<sub>2</sub>FeAl<sub>x</sub>Si<sub>1-x</sub> compounds |
| title_sort |
tuning the structural, magnetic and transport properties of full heusler co<sub>2</sub>feal<sub>x</sub>si<sub>1-x</sub> compounds |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2014 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1408984221 |
| work_keys_str_mv |
AT petersbrian tuningthestructuralmagneticandtransportpropertiesoffullheuslercosub2subfealsubxsubsisub1xsubcompounds |
| _version_ |
1719437002464559104 |