High Magnetocrystalline Anisotropy Research Articles

Effect of Ga substitution on grain orientation and magnetostrictive properties of polycrystalline CoFe2O4 ceramics prepared by the solid-state method

As a kind of magnetostrictive ceramics, cobalt ferrites are widely concerned because of its large magnetostriction and high resistivity, which are ideal for high-frequency applications. But, the high driving magnetic field due to the high magnetocrystalline anisotropy limits the practical applications of cobalt ferrites, thus, it is a still a challenge to find a balance between high magnetostriction properties and low driving magnetic fields. In this work, we investigated the effects of partially substitution of Ga3+ for Fe3+ on grain orientation and magnetic properties, attempting to maintain high magnetostriction while reducing the driving magnetic field. The CoFe2-xGaxO4 (x=0, 0.05, 0.1, 0.15) with single-phase spinel structure were prepared by the conventional solid-state method. The saturation magnetization MS increased with the increase of Ga concentration, meanwhile the coercivity Hc and magnetocrystalline anisotropy constant K1 significantly decreased, which indicates the better soft magnetic characteristics of the Ga-doped cobalt ferrites. The oriented CoFe2-xGaxO4 samples were obtained using magnetic field orientation technique during the powder forming process. The <001> preferred orientation was achieved in CoFe2O4 samples. However, the <001> orientation degree decreased with the substitution of Ga, and the preferred orientation has changed into <111> at x=0.15. The Ga substitution affected the magnetocrystalline anisotropy and grain orientation, thereby affecting the magnetostrictive properties. As for the non-oriented samples, although the maximum magnetostrictive strain slightly decreased with Ga substitution, while there was a significant drop in the magnetostrictive saturation field. However, the magnetostriction of the oriented samples decreased significantly with the substitution of Ga due to the change of grain orientation from <001> to <111>.

Effect of annealing temperature on crystallographic texture, magnetic and microwave properties of barium ferrite thin films

Due to it has large saturation magnetization (Ms), high magnetocrystalline anisotropy field and high ferromagnetic resonance (FMR) frequency, barium ferrite (BaM) has attracted more and more attentions in the fields of magnetic recording media, permanent magnets and microwave devices. Here, BaM thin films were deposited on Pt/TiO2/SiO2/Si substrates, and the effect of annealing temperature on the microstructure, magnetic and microwave properties of barium ferrite thin films was investigated in detail. It is found that when the BaM thin film was annealed at 1035 °C, it has good properties. The XRD data provide clear evidence that the BaM thin films have high c-axis orientation, and the Lotgering factor is as high as 0.96. The AFM morphology show that BaM grains are out of the film plane, and they are hexagonal. The magnetic hysteresis curves indicated that both saturated magnetization (4πMs), remanence ratio and coercive (Hc) for out of plane increase with increasing Ta first, then decreased, and get the maximum value at 1035 °C. The ferromagnetic resonance (FMR) measurement show that the FMR linewidth is 143 Oe@50 GHz, it means that this this sample has low microwave loss in millimeter wave loss, and the FMR absorption can be tuned by applied magnetic field. These results make sure that this BaM thin film is possible use in millimeter wave devices such as filers, circulators and isolators.

Robustness of magnetocrystalline anisotropy and coercivity in Fe–Co–B

As a potential candidate for critical chemical element free permanent magnet, (Fe0.7Co0.3)2B, shows promising intrinsic magnetic properties, including large magnetization, high Curie temperature and moderate magnetocrystalline anisotropy (MCA). Still, the coercivity that has been achieved is relatively low. To understand and improve coercivity, we study the robustness of MCA related to the fluctuation of chemical composition and the structural distortion and its effect on coercivity in (Fe0.7Co0.3)2B from first principles DFT (density functional theory) calculation and micromagnetic simulation. A fluctuation of cobalt content of 10%, or 1% isotropic lattice strain, or 2% tetragonal distortion reduces MCA energy up to 30%. By considering randomly distributed local MCA energy reduction up to 30%, the calculated coercivity of anisotropic bulk magnets reduced from 3.6 kOe to 2.2 kOe. Rational microstructure design, such as grain size refinement and development of strong crystal texture of MCA easy-axis (i.e., degree of alignment for (Fe0.7Co0.3)2B grains), can enhance coercivity and mitigate the effect of local MCA reduction. In addition to acceptable intrinsic magnetic properties, the promising hard magnetic phase needs good MCA robustness to facilitate the development of practical magnets.

Strain-controlled Néel temperature and exchange bias enhancements in IrMn/CoFeB bilayers

We propose a numerical method, where first-principles calculations are combined with modified Monte Carlo simulations, and study the Néel temperature of antiferromagnetic IrMn and exchange bias effect in antiferromagnet/ferromagnet IrMn/CoFeB bilayers manipulated by the applications of tensile and compressive strains. The results show that both tensile and compressive strains linearly change the magnetic moment of Mn and the magnetocrystalline anisotropy of IrMn, and meanwhile, the uniaxially easy-axis directions under tensile and compressive strains are perpendicular. The strain-triggered increase in antiferromagnetic exchange coupling between Mn–Mn pairs is revealed and induces an up to 1.5 times enhancement of the Néel temperature of IrMn. Furthermore, the spontaneous and conventional exchange bias effects can be both observed under large tensile strains, also sensitive to the cooling field, and strongly enhanced roughly by 800% under 8 T in the application of 1.5% strain, which can be interpreted by the strain-induced high magnetocrystalline anisotropies. Thus, the tensile strains are better for controlling and optimizing the Néel temperature of IrMn and further exchange bias properties in IrMn-based heterostructures. This work establishes the correlations between microscopically and macroscopically magnetic responses to strain, indicating that strain can be an intriguing means of extrinsic manipulation of exchange bias, which is of importance for spintronic device applications.

The effect of Nd content on the elemental interdiffusion mechanism of Nd–Dy–Fe–B magnets

In this work, the effect of Nd content on the interdiffusion mechanism of Nd/Dy elements in Nd-Dy-Fe-B magnets was elucidated by studying the differences in the magnetic properties, microstructure, and demagnetization process. As the Nd content increased, a uniform, continuous, and thicker layer of rare earth-rich (RE-rich) phase formed inside the magnets, which had a good magnetic isolation effect. During the demagnetization process, the strong ferromagnetic coupling effect between the main phase grains could be effectively weakened. At the same time, the thicker RE-rich phase layer could lead to a more obvious interdiffusion phenomenon of Nd/Dy elements, forming more (Nd, Dy)2Fe14B phases with high magnetocrystalline anisotropy fields, resulting in higher coercivity of the magnets. This paper elucidated the influence of Nd content on the interdiffusion mechanism of dual alloy Nd-Dy-Fe-B magnets, which had important significance for the preparation of high-performance Nd-Dy-Fe-B magnets.

Exceptional magnetic and magnetoelastic behavior of rare-earth non-centrosymmetric Sm7Pd3

Magnetic compounds possessing an intrinsic combination of near-zero magnetization with high magnetic anisotropy are highly desirable for spinronic applications and memory recording. A comprehensive study of Sm7Pd3 binary compound uncovered a unique combination of strong magnetoelastic behavior, very low net magnetization, and exceptionally high magnetic coercivity. The temperature-dependent X-ray synchrotron powder diffraction study indicates the abrupt changes in the compound's lattice parameters at the magnetic ordering temperature of TC=169 K, although the crystal structure remains non-centrosymmetric hexagonal Th7Fe3-type down to 6 K. Density functional theory calculations confirm high intrinsic magnetocrystalline anisotropy of Sm7Pd3, which explains the extremely large coercivity of the polycrystalline sample, up to Hcr = 130 kOe at 2 K. This discovery brings to life a novel class of highly anisotropic materials that are distinctly different from known spintronic materials, making them interesting future systems for magnetic memory research.

A Novel Spinel Ferrite-Hexagonal Ferrite Composite for Enhanced Magneto-Electric Coupling in a Bilayer with PZT.

The magnetoelectric effect (ME) is an important strain mediated-phenomenon in a ferromagnetic-piezoelectric composite for a variety of sensors and signal processing devices. A bias magnetic field, in general, is essential to realize a strong ME coupling in most composites. Magnetic phases with (i) high magnetostriction for strong piezomagnetic coupling and (ii) large anisotropy field that acts as a built-in bias field are preferred so that miniature, ME composite-based devices can operate without the need for an external magnetic field. We are able to realize such a magnetic phase with a composite of (i) barium hexaferrite (BaM) with high magnetocrystalline anisotropy field and (ii) nickel ferrite (NFO) with high magnetostriction. The BNx composites, with (100 - x) wt.% of BaM and x wt.% NFO, for x = 0-100, were prepared. X-ray diffraction analysis shows that the composites did not contain any impurity phases. Scanning electron microscopy images revealed that, with an increase in NFO content, hexagonal BaM grains become prominent, leading to a large anisotropy field. The room temperature saturation magnetization showed a general increase with increasing BaM content in the composites. NFO rich composites with x ≥ 60 were found to have a large magnetostriction value of around -23 ppm, comparable to pure NFO. The anisotropy field HA of the composites, determined from magnetization and ferromagnetic resonance (FMR) measurements, increased with increasing NFO content and reached a maximum of 7.77 kOe for x = 75. The BNx composite was cut into rectangular platelets and bonded with PZT to form the bilayers. ME voltage coefficient (MEVC) measurements at low frequencies and at mechanical resonance showed strong coupling at zero bias for samples with x ≥ 33. This large in-plane HA acted as a built-in field for strong ME effects under zero external bias in the bilayers. The highest zero-bias MEVC of ~22 mV/cm Oe was obtained for BN75-PZT bilayers wherein BN75 also has the highest HA. The Bilayer of BN95-PZT showed a maximum MEVC ~992 mV/cm Oe at electromechanical resonance at 59 kHz. The use of hexaferrite-spinel ferrite composite to achieve strong zero-bias ME coupling in bilayers with PZT is significant for applications related to energy harvesting, sensors, and high frequency devices.

Anomalous Nernst effect in perpendicularly magnetized τ-MnAl thin films

τ-MnAl is interesting for spintronic applications as a ferromagnet with perpendicular magnetic anisotropy due to its high uniaxial magnetocrystalline anisotropy. Here, we report on the anomalous Nernst effect of sputter deposited τ-MnAl thin films. We demonstrate a robust anomalous Nernst effect at temperatures of 200 and 300 K with a hysteresis similar to the anomalous Hall effect and the magnetization of the material. The anomalous Nernst coefficient of (0.6 ± 0.24) µV/K at 300 K is comparable to other perpendicular magnetic anisotropy thin films. Therefore, τ-MnAl is a promising candidate for spin-caloritronic research.

Crystal structure, magnetic and transport properties of Fe0.25TaSe2

The Fe0.25TaSe2 polycrystalline samples have been synthesized using two routes of solid-state reactions and various heat treatments and cooling conditions. The obtained samples have been studied by x-ray diffraction, magnetization and electrical resistivity measurements. It has been revealed that various methods of preparation and heat treatment do not have a strong effect on the lattice parameters of the main phase in the samples, but they significantly affect the magnetic critical temperature and magnetic hysteresis of the samples. Depending on the sample preparation procedure magnetic ordering temperature of Fe0.25TaSe2 is observed to vary in the range 33–60 K. The coercive field values from 31.7 kOe to 65.3 kOe at T = 2 K are indicative of a very high magnetocrystalline anisotropy in this material. The observed distinctions in the magnetic characteristics of the Fe0.25TaSe2 samples obtained by various methods and after different heat treatments can be ascribed to the difference in the distribution of Fe atoms over the crystal lattice.

Stable and metastable rare-earth-free permanent magnets from a database of predicted crystal structures

With the recent developments in crystal structure prediction, databases of new (not previously synthesized) materials are being created. One of these databases contains more than a million entries with the distance to the Convex Hull predicted by crystal-graph attention networks. Hence, stable and metastable materials can be extracted and then investigated for any desired properties. A high-throughput and data-mining approach we previously developed to search for rare-earth-free permanent magnets was applied to these compounds. As a result, four promising candidates for novel rare-earth-free permanent magnets were discovered with high magnetization, high uniaxial magnetocrystalline anisotropy, and high Curie temperature - Ta3ZnFe8, AlFe2, Co3Ni2, and Fe3Ge. The materials were investigated in more detail and all were verified to be dynamically stable.

Magnetic ordering in Ce substituted zirconite-YCrO4 nanostructures: focus on tunable energy bandgap and local-atomic environment

This study presents a comprehensive investigation of the structural, magnetic, electronic, and optical spectroscopic properties of tetragonal Zirconite Y1−x Ce x CrO4 polycrystals that were synthesized at various temperature ranges. The YCrO4 phase in its pristine state demonstrates ferromagnetic (FM) ordering, characterized by a Curie temperature, T C ∼ 9.3 K. Nevertheless, the introduction of magnetic Ce3+ in place of Y3+ ions results in a reduction of the T C and the appearance of a weak antiferromagnetic (AFM) behaviour, as indicated by the presence of a negative Curie–Weiss temperature (−10 K ≲ θ CW ≲ −30 K). It is observed that the introduction of moderate levels of Ce substitution leads to a significant increase in thermal irreversibility in the magnetization difference between field-cooled and zero-field-cooled states ΔM (M FC − M ZFC). This phenomenon indicates the substantial influence of magneto-crystalline anisotropy that exists within the system. Field-dependent magnetization data exhibits higher saturation magnetization values (M S ≳ (2.7 to 4.4) × 103 emu mole−1) and higher magneto-crystalline anisotropy (K 1 ∼ 2.18 to 3.41 J m−3) for the dilute dispersion of Ce (x ≤ 0.05). Local atomic environment probed by the electron spin resonance clearly indicates the presence of hyperfine splitting of Cr5+ spectra having a single d-electron () with orbital configuration bearing the possible doublet: On the other hand, the rare-earth Ce3+ spectra show hyperfine-doublets as and Finally, the energy band-gap (E g = 2.14 to 2.38 eV, for x ∼ 0 to 0.1) determined from the diffuse reflectance spectroscopy reveals the emergence of intermediate localized states upon substitution of Ce3+.

Atomic‐Scale Transition Zones Determined Coercivity in Samarium‐Cobalt Based Permanent Magnets

AbstractSmCo‐based permanent magnets with nanocellular structure exhibit significant advantage for high‐temperature applications. Due to the lack of experimental intrinsic magnetic parameters and unclear nanocellular interface, a fully understanding on coercivity mechanism is still limited. Here the intrinsic magnetic properties of designed two single‐phase alloys representing nanocellular structure at various temperatures are acquired. Using 3D atom probe and high‐angle annular dark‐field scanning transmission electron microscopy, the existence of the nanoscale transition zones located at nanocellular interface is revealed. Moreover, the transition zones exhibiting high magnetocrystalline anisotropy is found to contribute dominantly to the coercivity. The calculated coercivity via micromagnetic simulation considering transition zones agrees well with the tested coercivity at various temperatures. This knowledge deepens the fundamental understanding on coercivity mechanism.

Pr–Tb synergistic strengthening on coercivity of Nd-Ce-Fe-B magnets grain boundary diffused with Pr-Tb-Al-Ga alloys

Sintered Nd-Ce-Fe-B magnets were grain boundary diffused (GBDed) with PrxTb80–xAl10Ga10 (at%) (x = 0, 20, 40, 60, 80) alloys. The effect of Pr/Tb content in diffusion source on magnetic properties, microstructure and elements distribution of GBDed magnets was investigated. When Pr is used to substitute for 75% Tb in diffusion source, Tb consumption per unit coercivity improvement of GBDed magnet reduces by 77%, compared with the Tb80Al10Ga10 diffused magnet. Tb element diffuses into magnets and then forms Tb-rich shell with high magneto-crystalline anisotropy field surrounding main phase grains, resulting in substantial coercivity improvement. Pr with low melting point diffuses deeply along liquid grain boundary phase during GBD process. It can eliminate some sharp defects of main phase grains and make grain boundaries smooth, which provides diffusion channels for further diffusion of Tb element. Therefore, there are more diffusion channels for Tb and less Tb enriched at surface region, making Tb diffuse more deeply and improving Tb utilization efficiency. This method significantly improves the coercivity, and realizes the green, efficient and high-quality utilization of heavy rare earth (HRE) elements.

Emergence of net magnetization by magnetic field biased diffusion in antiferromagnetic L10 NiMn

NiMn is a collinear antiferromagnet with high magneto crystalline anisotropy ($K_2=-9.7\times10^5\;\text{J m}^{-3}$). Through magnetic annealing of NiMn with excess Ni, strongly pinned magnetic moments emerge due to an imbalance in the distribution of Ni in the antiferromagnetic Mn-sublattices. The results are explained with a model of magnetic-field-biased diffusion, supported by ab initio calculations. Another observation is the oxidation of Mn at the surface, causing an enrichment of Ni in the sub-surface region. This leads to an additional ferromagnetic response appearing in the magnetization measurements, which can be removed by surface polishing.

High-quality TbF3 coating prepared by suspension plasma spraying technique for improving the grain boundary diffusion efficiency of sintered Nd-Fe-B magnets

High-quality TbF3 coating used for the grain boundary diffusion process (GBDP) of sintered Nd-Fe-B was prepared by the suspension plasma spraying (SPS) technique. The obtained TbF3 coating with SPS process showed a dense and continuous structure with the uniform distribution as well as a good adhesion with the Nd-Fe-B substrate. Compared with the uncoated Nd-Fe-B magnet without heavy rare earth, the coercivity of TbF3 coated Nd-Fe-B magnet enhanced from 1160 kA/m to 1824 kA/m after the GBDP heat treatment. The microstructure and composition analysis indicated that the (Nd, Tb)2Fe14B shell formed at the periphery of Nd2Fe14B grains throughout the whole sample magnet. The shell with high magnetocrystalline anisotropy effectively suppressed the nucleation of reverse domain and repaired the defects on the grain surface of the sintered Nd-Fe-B magnets, thus enhancing the coercivity. As a consequence, the SPS technology has advantage of high depositing rate, flexible production process, good boundary adhesion and homogeneous-dense structure, which is expected to become a promising candidate way of depositing diffusion coating for the GBDP of sintered Nd-Fe-B in industrial production.

Structure and Performance Optimization of Co Magnetic Thin Films Deposited by Vacuum Evaporation Coating.

Co magnetic films are widely used in high-frequency magnetic recording and vertical magnetic recording due to their high saturation magnetization and magnetocrystalline anisotropy. In this work, ferromagnetic Co magnetic films were prepared on copper substrate by vacuum evaporation combined with heat treatment (H2 atmosphere), to investigate the impact of film thickness and annealing temperature on microstructure and magnetic properties. The results show that with the increase in annealing temperature, the Co thin film physical phase does not change significantly, the crystallinity increases, and the grain size increases, which is consistent with the results obtained from the SEM morphology map of the sample surface, leading to an increase in coercivity. By annealing experiments (atmospheric atmosphere) on Co magnetic films with and without an Al protective layer, as shown by scanning electron microscopy microscopic characterization results, it was verified that the Al layer can protect the inner Co layer from oxidation. As the film thickness increases from 10 to 300 nm, the magnetic properties of Co films change significantly. The saturation magnetization gradually increases from 0.89 to 5.21 emu/g, and the coercivity increases from 124.3 to 363.8 Oe. The remanence ratio of the 10 nm magnetic film is 0.82, which is much higher than the film remanence ratio of 0.46 at 50 nm. This is because when the thickness of the film is between 10 and 50 nm, the magnetic moments partially deviate from the in-plane direction, and the out-of-plane component reduces the film remanence ratio. This study shows that optimizing annealing temperature and film thickness can effectively control the structure and magnetic properties of Co magnetic films, which is of great significance for the development of the magnetic recording field.

Microstructure and magnetic properties of grain boundary diffused Nd-Fe-B magnets with Tb-Al-Ga alloy

The coercivity of Nd-Fe-B magnets can be effectively improved by grain boundary diffusion using low melting point alloy as diffusion source. In this work, Tb-Al-Ga alloy was used as diffusion source for grain boundary diffused Nd-Fe-B magnets. Tb-rich shell structure, potential synergistic effect of Al-Ga, interface between diffusion source and the magnets were analyzed. When the magnets were processed at 875 °C for 10 h, the coercivity increased by 123 % from 10.38 kOe to 23.15 kOe and the remanence and the maximum magnetic energy product only decreased by 3 %. Tb element mainly formed shell structure with high magneto-crystalline anisotropy field surround the main phase grains. Non-magnetic Al element was distributing around the main phase grains as network structure, which could well isolate the main phase grains. The Tb-rich shell with high magneto-crystalline anisotropy field and the non-magnetic phase with magnetic exchange decoupling between the adjacent grains contributed to substantial increase in the coercivity of the grain boundary diffused magnets. The grain boundary phase was wetted by Al element, which promoted Tb element diffused into the magnets more deeply.

Microstructure regulation and optimizing magnetic properties of (La, Ce, Pr)17Fe78B6 alloy via short-range grain boundary diffusion

Increasing the utilization ratio of La and Ce in rare earth permanent magnets is an effective measure to solve the balance utilization of rare earth resources. In this work, nanocrystalline melt spun [(Ce0.7La0.3)0.3Pr0.7]17Fe78B6 powder and low melting point PrTbCu alloy were used as the initial material and the diffusion source for short-range grain boundary diffusion (SRGBD) to improve the coercivity. High coercivity of up to 18.21 kOe can be achieved, enhancing by 108.82% compared with the initial powder, and meanwhile, the remanence was only slightly reduced by 2.13%. After that, nanocrystalline bulk magnets with excellent magnetic performance were produced through spark plasma sintering (SPS). TEM observation reveals that the bcc-RE2O3 intergranular phase that induced by short-range grain boundary diffusion is distributed between adjacent matrix phase grains, which is conductive to the improvement of magnetic isolation effect. EDS results show that the Tb-rich shell with high magnetocrystalline anisotropy field has formed. Moreover, it is found that Tb diffuses into the 2:14:1 phase more easily than Pr element during the initial stage of diffusion. Enhanced magnetic isolation effect and the formed Tb-rich shell in grain surface contributed to high coercivity.

Effect of High-Anisotropic Co2+ Substitution for Ni2+ on the Structural, Magnetic, and Magnetostrictive Properties of NiFe2O4: Implications for Sensor Applications.

This work reports on the effect of substituting a low-anisotropic and low-magnetic cation (Ni2+, 2μB) by a high-anisotropic and high-magnetic cation (Co2+, 3μB) on the crystal structure, phase, microstructure, magnetic properties, and magnetostrictive properties of NiFe2O4 (NFO). Co-substituted NFO (Ni1-xCoxFe2O4, NCFO, 0 ≤ x ≤ 1) nanomaterials were synthesized using glycine-nitrate autocombustion followed by postsynthesis annealing at 1200 °C. The X-ray diffraction measurements coupled with Rietveld refinement analyses indicate the significant effect of Co-substitution for Ni, where the lattice constant (a) exhibits a functional dependence on composition (x). The a-value increases from 8.3268 to 8.3751 Å (±0.0002 Å) with increasing the "x" value from 0 to 1 in NCFO. The a-x functional dependence is derived from the ionic-size difference between Co2+ and Ni2+, which also induces grain agglomeration, as evidenced in electron microscopy imaging. The chemical bonding of NCFO, as probed by Raman spectroscopy, reveals that Co(x)-substitution induced a red shift of the T2g(2) and A1g(1) modes, and it is attributed to the changes in the metal-oxygen bond length in the octahedral and tetrahedral sites in NCFO. X-ray photoelectron spectroscopy confirms the presence of Co2+, Ni2+, and Fe3+ chemical states in addition to the cation distribution upon Co-substitution in NFO. Chemical homogeneity and uniform distribution of Co, Ni, Fe, and O are confirmed by EDS. The magnetic parameters, saturation magnetization (MS), remnant magnetization (Mr), coercivity (HC), and anisotropy constant (K1) increased with increasing Co-content "x" in NCFO. The magnetostriction (λ) also follows a similar behavior and almost linearly varies from -33 ppm (x = 0) to -227 ppm (x = 1), which is primarily due to the high magnetocrystalline anisotropy contribution from Co2+ ions at the octahedral sites. The magnetic and magnetostriction measurements and analyses indicate the potential of NCFO for torque sensor applications. Efforts to optimize materials for sensor applications indicate that, among all of the NCFO materials, Co-substitution with x = 0.5 demonstrates high strain sensitivity (-2.3 × 10-9 m/A), which is nearly 2.5 times higher than that obtained for their intrinsic counterparts, namely, NiFe2O4 (x = 0) and CoFe2O4 (x = 1).

Constituent contribution to the magnetocrystalline anisotropy in Mn(Al1−xGax)

The phase stability and magnetocrystalline anisotropy (MCA) of tetragonal Mn(Al1−xGax) with the L10-type structure (P4/mmm) has been studied using first-principles density functional calculations. The calculated decomposition energy indicates that partial replacement of Al by Ga suppresses the formation of Mn5(Al,Ga)8 and enhances the thermal stability of the L10 phase while the total magnetic moment per formula unit (f.u.) remains almost unchanged. The site- and atomic-resolved MCA calculations show that the MCA energy (MAE) comes mainly from the Mn atoms, and the total MAE increases from 0.25 meV/f.u. (x = 0) to 0.34 meV/f.u (x = 1). Spin resolved MCA and band structure calculations indicate that the high MCA is mainly due to spin flipping behavior near Fermi level. The derived effective magnetic anisotropy field increases from 37 kOe (x = 0) to 46 kOe (x = 1), in agreement with experiments. Doping with Ga improves the thermal stability of the L10 structure and enhances the magnetic anisotropy field, which facilitates developing high coercivity Mn-Al magnets.