Distinguishing local moment versus itinerant ferromagnets: Dynamic magnetic susceptibility

Abstract

Radio-frequency measurements of dynamic magnetic susceptibility of various ferromagnets show striking differences between local-moment ferromagnetism (LFM) and weak itinerant ferromagnetism (IFM) ferromagnetic systems. LFMs show a very sharp peak in susceptibility in the vicinity of the Curie temperatureTC that rapidly decreases in amplitude and shifts to higher temperature with the application of a weak dc bias field. In stark contrast, the generally accepted IFM systems show no peak, but rather a broad maximum well below TC. The temperature of this maximum shifts to lower values and the amplitude is suppressed with an applied dc field. KeywordsPhysics and Astronomy, Zinc, Ferromagnetism, Alternating current power transmission, Magnetic susceptibilities, Coils Disciplines Condensed Matter Physics CommentsThe following article appeared in Journal of Applied Physics (2008) Radio-frequency measurements of dynamic magnetic susceptibility of various ferromagnets show striking differences between local-moment ferromagnetism ͑LFM͒ and weak itinerant ferromagnetism ͑IFM͒ ferromagnetic systems. LFMs show a very sharp peak in susceptibility in the vicinity of the Curie temperature T C that rapidly decreases in amplitude and shifts to higher temperature with the application of a weak dc bias field. In stark contrast, the generally accepted IFM systems show no peak, but rather a broad maximum well below T C . The temperature of this maximum shifts to lower values and the amplitude is suppressed with an applied dc field.

Cluster-glass behavior induced by local moment doping in the itinerant ferromagnet Sc3.1In

“…4 A possible solution is to use a purely itinerant electron ferromagnet compound in which all constituents are nonmagnetic, and then titrate in local moment-bearing ions. Currently, only two compounds, ZrZn 2 (Ref.…”

Dynamic magnetic susceptibility of systems with long-range magnetic order

“…In some concentrations the application of magnetic field also uncovers other features. This is most evident in the 50% cobalt doped sample where in fields of 0.6-1.1 kOe a well-defined peak in χ is observed in the vicinity of 20 K. Previous TDR rf susceptibility studies on other magnetic materials have shown that the presence of a well defined peak is indicitative of the onset of local moment ferromagnetic order [Vannette et al (2008d), Vannette et al (2008a), Vannette and Prozorov (2008)]. As the introduction of cobalt ions into the parent GdFe 2 Zn 20 lattice has been shown to suppress the itinerant component of the magnetism, the observation of features strongly associated with local moment magnetic order is not surprising.…”

Low-temperature high-frequency dynamic magnetic susceptibility of classical spin-ice Dy$_2$Ti$_2$O$_7$

“…The tunnel diode resonator technique is widely used for precision radio frequency (rf) magnetic susceptibility measurements of magnetic and superconducting materials with 1 : 10 7 frequency resolution measuring better than 0.1 Hz frequency shift at 10 MHz [34,35,30,31]. While in metallic samples the signal is a combination of skin effect and spin susceptibility, in insulating materials, such as the present case of spinice, it gives directly the real part of rf AC susceptibility up to a constant geometric factor.…”