  The design and synthesis of targeted functional materials have been a
long-term goal for material scientists. Although a universal design strategy is
difficult to generate for all types of materials, however, it is still helpful
for a typical family of materials to have such design rules. Herein, we
incorporated several significant chemical and physical factors regarding
magnetism, such as structure type, atom distance, spin-orbit coupling, and
successfully synthesized a new rare-earth-free ferromagnet, MnPt5As, for the
first time. MnPt5As can be prepared by using high-temperature pellet methods.
According to X-ray diffraction results, MnPt5As crystallizes in a tetragonal
unit cell with the space group P4/mmm (Pearson symbol tP7). Magnetic
measurements on MnPt5As confirm ferromagnetism in this phase with a Curie
temperature of ~301 K and a saturated moment of 3.5 uB per formula. Evaluation
by applying the Stoner Criterion also indicates that MnPt5As is susceptible to
ferromagnetism. Electronic structure calculations using the WIEN2k program with
local spin density approximation imply that the spontaneous magnetization of
this phase arises primarily from the hybridization of d orbitals on both Mn and
Pt atoms. The theoretical assessments are consistent with the experimental
results. Moreover, the spin-orbit coupling effects heavily influence on
magnetic moments in MnPt5As. MnPt5As is the first high-performance magnetic
material in this structure type. The discovery of MnPt5As offers a platform to
study the interplay between magnetism and structure.
