Body-centered-cubic Ni and its magnetic properties

Area of Science:

• Materials Science
• Condensed Matter Physics
• Magnetism

Background:

• Nickel typically exists in a face-centered-cubic (fcc) crystal structure.
• The body-centered-cubic (bcc) phase of nickel is not found naturally.
• Understanding different crystallographic phases is crucial for tuning material properties.

Purpose of the Study:

• To synthesize and characterize the non-existent body-centered-cubic (bcc) phase of nickel.
• To investigate the magnetic properties of bcc nickel thin films.
• To compare the magnetic anisotropy of bcc and fcc nickel.

Main Methods:

• Thin film deposition of nickel on GaAs(001) substrate using molecular beam epitaxy at 170 K.
• Ferromagnetic characterization including Curie temperature and magnetic moment measurements.
• Determination of cubic magnetocrystalline anisotropy.
• Electronic band structure analysis using angle-resolved photoemission spectroscopy with synchrotron radiation.

Main Results:

• Successfully synthesized a stable body-centered-cubic (bcc) nickel thin film.
• The bcc Ni phase is ferromagnetic with a Curie temperature of 456 K and a magnetic moment of 0.52+/-0.08 micro(B)/atom.
• Exhibits a cubic magnetocrystalline anisotropy of +4.0x10^5 ergs x cm^-3, significantly different from fcc Ni (-5.7x10^4 ergs x cm^-3).

Conclusions:

• The synthesis of the metastable bcc Ni phase is achievable under specific conditions.
• Significant differences in magnetic anisotropy between bcc and fcc Ni are observed.
• These magnetic property variations are attributed to distinct electronic band structures of the two nickel phases.