English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report on a study on a representative set of Fe$_{2}$P-based MnFePSisamples by means of $^{55}$Mn NMR in both zero and applied magnetic field. Thefirst-order nature of the magnetic transition is demonstrated by truncatedorder parameter curves with a large value of the local ordered moment at theCurie point, even at compositions where the transition appears second orderfrom magnetic measurements. No weak ferromagnetic order could be detected atSi-poor compositions showing the kinetic arrest phenomenon, but rather thephase separation of fully ferromagnetic domains from volume fractions where Mnspins are fluctuating. The more pronounced decrease of the ordered moment atthe $3f$ sites on approaching $T_C$, characteristic of the mixed magnetism ofthese materials, is demonstrated to be driven by a vanishing spin densityrather than enhanced spin fluctuations at the $3f$ site. An upper limit of0.03~$\mu_B$ is set for the fluctuating Mn moment at the $3f$ site by thedirect detection of a $^{55}$Mn NMR resonance peak in the Mn-rich samples above$T_C$, showing nearly temperature-independent frequency shifts. A sharpersecondary peak observed at the same compositions reveals however thedisproportionation of a significant $3f$-Mn fraction with negligible hyperfinecouplings, which retains its diamagnetic character across the transition, downto the lowest available temperatures. Such a diamagnetic fraction qualitativelyaccounts for the reduced average $3f$ moment previously reported at large Mnconcentrations.

Mixed magnetism, nanoscale electronic segregation and ubiquitous first  order transitions in giant magnetocaloric MnFeSiP alloys detected by  $^{55}$Mn NMR