Half-metallic Heusler alloys are of high interest to the material research community due to their potential application in spintronic devices. We have synthesized one such compound, CoFeVGe, using arc melting and high-vacuum annealing at 600oC for 48 hours. The room temperature x-ray diffraction of the sample exhibits a cubic crystal structure without secondary phases. The sample shows a single magnetic transition at its Curie temperature of 249 K, Fig. 1(a). The high field (3T) magnetization measured at 100 K is 41 emu/g. We also observed that the Curie temperature of the sample can be increased to near room temperature with slightly changing the elemental composition. The sample with composition Co1.25Fe0.75VGe remains cubic in crystal structure, and it exhibits a Curie temperature of 294 K and saturation magnetization at 100 K of 36 emu/g. Our first principle calculations of CoFeVGe and Co1.25Fe0.75VGe in their cubic crystal structures predict a high degree of spin polarization of 86% and 82%, respectively. Figure 1(b) shows the calculated element- and spin- resolved density of states for CoFeVGe. These results indicate that Co1.25Fe0.75VGe has a potential for near room temperature spintronic applications.
This research is supported by the National Science Foundation (NSF) under Grant Numbers 2003828 and 2003856 via DMR and EPSCoR. 

![](https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/d3202f2cb9992e34de920c2dc61c9236.png)

Structural and Magnetic Properties of CoFeVGe: Experiment and Theory

Materials showing half-metallic band structure with a high Curie temperature and moderate magnetization are attractive for spin-transport-based devices. Some Heusler compounds exhibit these features and have attracted much attention. We have synthesized one such compound, Co1.5Mo0.5FeAl, using arc melting and high vacuum annealing. The arc-melted ingot was annealed at 600 oC for 48 hours. The room temperature x-ray diffraction suggests that the sample has cubic crystal structure with A2 type disorder. The temperature dependence of magnetization measured at 1 kOe shows a very high Curie temperature of about 950 K. There is an anomaly in the M(T) curve near 750 K, Fig.1. The sample exhibits a moderate saturation magnetization of 68 emu/g at room temperature. These results show that Co1.5Mo0.5FeAl has potential for high temperature magnetic and spintronic applications. Here, we will also discuss the electronic and magnetic properties of cubic Co1.5Mo0.5FeAl predicted by our first principles calculations.
This research is supported by the National Science Foundation (NSF) under Grant Numbers 2003828 and 2003856 via DMR and EPSCoR. 

![](https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/68492170baaecab300d447527fc392fb.png)

Structural and Magnetic Properties of Co1.5Mo0.5FeAl Alloy

Materials exhibiting high degree of spin polarization such as half-metals or spin-gapless semiconductors are in demand for spin-transport-based devices. Especially, half metallic Heusler compounds have attracted much attention because they have tunable magnetic properties and exhibit high Curie temperature much above room temperature. We have synthesized one such predicted half metal, FeCrVAl, using arc melting and annealing. The vacuum annealing was done at 600oC for 48 hours. In addition, we also studied the effect of Mn substitution on the structural, magnetic, and electronic band properties of FeCrVAl synthesizing samples with compositions FeCr0.5Mn0.5VAl and FeCrV0.5Mn0.5Al. The room temperature, x-ray diffraction patterns indicate that FeCrVAl and FeCrV0.5Mn0.5Al are cubic in structure with A2 type disorder, whereas FeCr0.5Mn0.5Val is more ordered as evidenced by the presence of superlattice peaks. All samples show small saturation magnetizations at room temperature and the thermomagnetic curves M(T) are similar to that of a paramagnetic material. However, as shown in Fig.1 below, the M(T) of FeCr0.5Mn0.5VAl is different and shows a slow magnetic transitionat 800 K similar to that of a ferrimagnetic material. In this presentation, we will discuss the structural, magnetic and electron band properties of the synthesized materials and the effect of disorder on the properties of FeCrVAl. This research is supported by the National Science Foundation (NSF) under Grant Numbers 2003828 and 2003856 via DMR and EPSCoR.

![](https://assets.underline.io/uploads/markdown_image/1/image/671008ce0e34982996f2b9cfad55899c.jpg)

Figure 1: Thermomagnetic curve M(T) of FeCr0.5Mn0.5VAl alloy. The inset shows the M (H) curve recorded at 300 K.

Experimental and theoretical investigation of FeCrVAl and related compounds

Combining perpendicular magnetic anisotropy (PMA) with half-metallicity (HM) in thin-film geometry may provide additional functionalities for spintronic devices. However, such combination may be a challenging task, since HM is usually destroyed in thin-film geometry (e.g., due to the emergence of surface states), while PMA is most pronounced in reduced geometry, because of the contribution from surface anisotropy. Here, we explore the nature of PMA in thin-film full Heusler alloy Co2MnSi. This material is one of the first compounds for which half-metallic electronic structure was experimentally confirmed. In addition, it has been reported that this alloy may exhibit PMA in thin-film geometry. Here, by analyzing site-projected magnetocrystalline anisotropy energy (MAE), we confirm that both PMA and surface half-metallicity are very sensitive to the termination surface and mechanical strain. In particular, while MnSi-termination under compressive strain may retain both 100% spin-polarization and out-of-plane magnetization orientation, Co-termination has a detrimental impact on both. These results may serve as a guide for practical nano-device applications in the field of spintronics. This research is supported by the National Science Foundation (NSF) under Grant Numbers 2003828 and 2003856 via DMR and EPSCoR.

First principles study of perpendicular magnetic anisotropy in thin-film Co2MnSi

Research on rare-earth-free permanent magnet materials have attracted much attention due to the limited supply and high price of the rare-earth metals used in current state-of-the-art permanent magnets. MnBi and MnBi-based magnets have been investigated as prospective rare-earth-free magnets because the magnetic anisotropy of MnBi increases with increasing temperature reaching a maximum value at 590 K. However, segregation of Bi during synthesis of MnBi is one of the issues which reduces the saturation magnetization. We have found that MnBi synthesized in carbon environment substantially reduces the amount of Bi segregation improving its saturation magnetization. We have synthesized Mn55Bi45 and Mn55Bi45C samples using arc melting and high vacuum annealing. The room temperature x-ray diffraction patterns indicate that both Mn55Bi45 and Mn55Bi45C crystallize in the hexagonal NiAs crystal structure (Low temperature phase, LTP). The X-ray diffraction pattern also indicates that the amount of Bi segregation in Mn55Bi45C is less than that in MnBi. As shown in Fig. 1 below, the high field (3T) magnetization measured at room temperature are 61 emu/g and 66 emu/g for Mn55Bi45 and Mn55Bi45C, respectively. There is small increase in the value of anisotropy constant due to carbon doping. In order to find the possibility of carbon occupying the MnBi lattice, we have carried out first principles calculations of MnBi alloy as well. The conclusions of the first principles calculation and experimental data on structural and magnetic properties of Mn55Bi45 and Mn55Bi45C will be presented. This research is supported by South Dakota-NASA EPSCoR Research Initiation Grant no 80NSSC19M0063.

![](https://assets.underline.io/uploads/markdown_image/1/image/e0f6f2e16ebf3f5ccde46e9f75d13c25.jpg)

Fig. 1: Isothermal magnetization curves M(H) for Mn55Bi45 and Mn55Bi45C measured at 300 K. Inset shows the M(H) curve for Mn55Bi45C after aligning in magnetic field.

Modifying magnetic properties of MnBi with Carbon: An experimental and theoretical study

Half-metallic Heusler alloys have attracted much attention due to their potential application in spin-transport-based devices. We have synthesized one such alloy, CoFeV0.5Mn0.5Si, using arc melting and high-vacuum annealing. The vacuum annealing was done at 600oC for 24 hours. First principles calculation indicates that CoFeV0.5Mn0.5Si shows nearly half-metallic band structure with the degree of spin polarization of about 93%. The room temperature x-ray diffraction patterns are indexed with the cubic crystal structure without disorder and secondary phases. The annealed sample show ferromagnetic order with the Curie temperature well above room temperature (Tc = 657 K) and the high-field (3T) magnetization at room temperature of about 83 emu/g. Figure 1 below shows the magnetization as a function of temperature of CoFeV0.5Mn0.5Si measured at 1 kOe which shows a smooth magnetic transition at the Curie temperature. The observed structural and magnetic properties are consistent with the theoretical results and these results indicate that CoFeV0.5Mn0.5Si has a potential for room temperature spin-transport-based devices. This research is supported by the National Science Foundation (NSF) under Grant Numbers 2003828 and 2003856 via DMR and EPSCoR.

![](https://assets.underline.io/uploads/markdown_image/1/image/bd63234b2eeb383951e6554ddc76dd14.jpg)

Figure 1: Thermomagnetic curve M(T) of CoFeV0.5Mn0.5Si alloy. The inset shows the dM/dT versus T curve

Electronic band structure and magnetism of CoFeV0.5Mn0.5Si

BOB: Multiferroic, Magnetoelectric and Half-Metallic Materials

technical paper

#### Welcome to the 67th Annual Conference on Magnetism and Magnetic Materials, MMM 2022!

The Conference was held from October 31 to November 4 and offers both in-person and on-demand content.

MMM 2022 is sponsored jointly by AIP Publishing and the IEEE Magnetics Society. Members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism are invited to attend and contribute to the technical sessions. The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a tutorial, and several special sessions. This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

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MMM 2022

This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

**Please click on the poster to see the abstract or leave your comment to the author.** 
**Session Chair:** Ying-Hao Chu, *National Yang Ming Chiao Tung University*

BPA: Multiferroics, Magnetoelectrics, Complex Oxides and Half-Metallics

poster

**Session chair:** Atsufumi Hirohata, University of York



BOA - Magnetoelectronic Materials and Phenomena: Heuslers and Related Materials

The 15th Joint MMM-INTERMAG Conference (2022 Joint) is sponsored jointly by AIP Publishing and the IEEE Magnetics Society. Members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism are invited to attend and contribute to the technical sessions. The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a plenary session, and an evening session, with about 1500 presentations overall. This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

The 2022 Joint Conference will offer both in-person and prerecorded on-demand content.

For tickets to the event, please register at the following link: https://magnetism.org/register

Please register for the Joint MMM-Intermag conference to join the event.

2022 Joint MMM-INTERMAG

**Session chairs:** Melissa Loving, Northrop Grumman Corporation and Susana de Freitas, INESC-MN



EOE - Thin Films ΙΙ

**Session chairs:** Xubo Liu, Ames Laboratory and Jeotikanta Mohapatra, University of Texas at Arlington



DPA - Permanent Magnets and Processing II

**Session chair:** Luis Moreno-Ramírez, Universidad de Sevilla



Parashu Kharel

6

18

SHORT BIO

Presentations

Structural and Magnetic Properties of CoFeVGe: Experiment and Theory

Structural and Magnetic Properties of Co1.5Mo0.5FeAl Alloy

Experimental and theoretical investigation of FeCrVAl and related compounds

First principles study of perpendicular magnetic anisotropy in thin-film Co2MnSi

Modifying magnetic properties of MnBi with Carbon: An experimental and theoretical study

Electronic band structure and magnetism of CoFeV0.5Mn0.5Si

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