Magnetic Phase Stability Research Articles

New insight into tuning magnetic phases of RMn6Sn6 kagome metals

Predicting magnetic ordering in kagome compounds offers the possibility of harnessing topological or flat-band physical properties through tuning of the magnetism. Here, we examine the magnetic interactions and phases of ErMn6Sn6 which belongs to a family of RMn6Sn6, R = Sc, Y, Gd–Lu, compounds with magnetic kagome Mn layers, triangular R layers, and signatures of topological properties. Using results from single-crystal neutron diffraction and mean-field analysis, we find that ErMn6Sn6 sits close to the critical boundary separating the spiral-magnetic and ferrimagnetic ordered states typical for non-magnetic versus magnetic R layers, respectively. Finding interlayer magnetic interactions and easy-plane Mn magnetic anisotropy consistent with other members of the family, we predict the existence of a number of temperature and field dependent collinear, noncollinear, and noncoplanar magnetic phases. We show that thermal fluctuations of the Er magnetic moment, which act to weaken the Mn-Er interlayer magnetic interaction and quench the Er magnetic anisotropy, dictate magnetic phase stability. Our results provide a starting point and outline a multitude of possibilities for studying the behavior of Dirac fermions in RMn6Sn6 compounds with control of the Mn spin orientation and real-space spin chirality.

Magnetic properties and microstructure of Ce and Zr synergetic stabilizing Ti-lean SmFe12-based strip-casting flakes

Recently ThMn12-type samarium iron alloys have been promising materials for permanent magnets. Due to the high abundance and low cost, Ce as a possible stabilizer can be introduced into ThMn12-type alloys. The effect of Ce doping on the magnetic moment and phase stability in Ti-lean (Ce,Sm,Zr)(Fe,Co,Ti)12 compounds were predicted by the first-principles calculations. The CexSm0.8-xZr0.2(Fe0.8Co0.2)11.5Ti0.5 (x = 0–0.8) alloys with ThMn12 structure were produced by strip-casting into flakes by a wheel speed of 1.5 m/s and annealed at 1000 °C for 24 h. The Ce0.8Zr0.2(Fe0.8Co0.2)11.5Ti0.5 annealed flake shows a high saturation magnetization value of 13.6 kGs at room temperature. With the increase of Ce substitution in the annealed flakes, the content of α-(Fe,Co,Ti) phase decreases and the saturation magnetization increases. The 1:12 phase and the 1:9 phase have an orientation relationship that can be expressed as [0 0 –1]1:12//[100]1:9 and (020)1:12//(010)1:9. Besides, annealing process promotes the formation of 1:12 phase transformed from 1:9 phase. Coercivity is expected to be improved by obtaining uniform microstructure and suppressing the formation of soft α-(Fe,Co,Ti) phase in the ThMn12-based alloys.

Density functional study of electrode material for magnetic tunnel junction designed using Co2TiZ (Z = Ge, Si) Heusler alloys

Some of the important applications in the field of spintronics are spin current driven logic devices having logic gates and in read heads in the hard disk drives, magnetic random access memory (MRAM) containing non-volatile memory units and extremely complex magnetic sensor. In spintronic applications, a magnetic tunnel junction (MTJ) is considered the back bone of all such devices. With this motivation, in present study we have predicted very low resistance area (RA) product value and high tunnel magneto resistance (TMR) of two designed MTJs by using full Heusler alloys (FHA) Co2TiZ (Z = Ge, Si) as electrode and MgO as barrier layer. These used half metallic (HM) Heusler alloys (HA), have been investigated using Wien2K code, via primary standard calculations and studied electronic and magnetic properties followed by structural and magnetic phase stability. Spin based band structure along with density of state (DOS) profiles are determined by considering both generalized gradient approximation (GGA) + modified Becke–Johnson functional (mBJ) functional and GGA potentials. For the estimation of the Curie temperature (Tc) mean field approximation (MFA) was considered. After determining physical properties of considered FHAs, spin polarised transport properties are calculated by using PWCOND code embedded in Quantum ESPRESSO (QE) for designed MTJs and obtained extremely low resistance-area product (RA) product and a high value of TMR which is found very suitable for spintronic device applications.

Acoustic shock wave recovery experiments on cubic zinc sulfide nanoparticles for electrical and magnetic switches applications

In the present work, we report acoustic shock wave recovery experimental findings on cubic zinc sulfide nanoparticles (ZnS NPs) with crystallographic, electronic and magnetic phase stability. The acquired X-ray diffraction (XRD) and magnetic results show that the ZnS NPs have a stable cubic crystalline structure, and however, owing to the reduction in defects, they result in reversible magnetic phase transitions from the weak-ferromagnetic to mixed-diamagnetic/ferromagnetic states at the corresponding 50 and 150 shocked conditions. The values of saturation magnetization are determined as 0.249, 0.052, 0.249 and 0.049 emu/g for 0, 50, 100 and 150 shocked conditions, respectively. Accordingly, the magnitude of the calculated band gap energies for 0, 50, 100 and 150 shocked conditions are identified to be 3.70, 3.85, 3.69, and 3.85 eV, respectively. Furthermore, the double peaks at corresponding positions of 161.67 (S 2p3/2) and 162.97 (S 2p1/2) of the X-ray photoelectron spectroscopy (XPS) are converted into the singlet peak at 162.23 (S 2p1/2), demonstrating the reduction of the defect density at the 50-shocked condition. Finally, the structure-property relationship of cubic ZnS NPs and magnetic properties with respect to the exposed shocks are discussed in detail. Due to the switchable optical and magnetic properties by the number of shock pulses, cubic zinc sulfide nanoparticles can be suitable for spintronics devices and magnetically switchable applications.

Magnetocaloric Effect In Full-Heusler Rh2SmIn Compound Based on Rare Earths Using DFT and Monte Carlo Studies

Abstract Magnetocaloric refrigeration is an integral part of technology and is under constant investigation. In this regard, the characterization of the magnetocaloric materials used is of major concern. In this study, we used different approaches to better understand the mechanisms underlying the magnetic and magnetocaloric properties of Rh 2 S mIn Full-Heusler. A physical model is suggested to explain the magnetic interaction within this material. Utilizing the density functional theory, exchange couplings and magnetic phase stability in Rh 2 SmIn have been attempted as well in order to understand and clarify the various magnetic interactions in this compound. The magnetic and magnetocaloric properties were examined with Monte Carlo simulation (MCS) based on the Ising model. The transition temperature, magnetic entropy change, and relative cooling power (RCP) were computed and found to be in good agreement with experimental evidence. According to the results, Rh 2 S mIn is a good candidate to be used in magnetic refrigeration applications at high temperature.

Origin of spin glass magnetic behavior and phase stability of flux-grown RE(Al, Cr, Fe)B4 (RE = Ho and Er) single crystals

The YCrB4 type (α-phase, orthorhombic with space group Pbam) α-HoAlB4 and α-ErAlB4 single crystals which were self-flux grown exhibit the spin glass magnetic behavior, which is anomalous compared to the other reported rare earth system phases of α-REAlB4. Local atomic arrangements with the atomic-resolution for α-HoAlB4 and α-ErAlB4 compounds have been investigated by spherical aberration (Cs)-corrected scanning transmission electron microscopy (STEM) with high-angle annular detector dark-field (HAADF) and annular bright-field (ABF), and STEM-energy-dispersive X-ray spectroscopy (EDS) techniques to elucidate the origin of the exotic magnetic behavior. Observed HAADF- and ABF-STEM images and STEM-EDS chemical maps taken with the incident beam parallel to the [001] direction clearly indicate the existence of substitutions for Al atom sites. The phase stability of RAlB4 (R = Ho ∼ Lu) compounds was discussed from the viewpoint of crystallographic features with lattice parameters and compositions. Based on the presented results, it could be concluded that the origin of the spin glass behavior for self-flux grown α-HoAlB4 and α-ErAlB4 single crystals is the unexpected substitution of Cr/Fe atoms for Al ones. Simultaneously, the substitution by Cr/Fe atoms for Al atoms is indicated to play a significant role to stabilize the YCrB4-type α-HoAlB4 and α-ErAlB4 compounds.

Identification of a Magnetic Phase via a Raman Spectrum in Single-Layer MnSe: An ab Initio Study

Motivated by the recent experimental realization of single-layer two-dimensional MnSe [ACS Nano2021, 15, 13794–13802], structural, magnetic, elastic, vibrational, and electronic properties of single-layer MnSe are investigated by using density functional theory-based calculations. Among four different magnetic phases, namely, ferromagnetic (FM) and Nẽel-, zigzag-, and stripy-antiferromagnetic (AFM) phases, the Nẽel-AFM structure is found to be the energetically most favorable phase. Structural optimizations show the formation of in-plane anisotropy within the structures of zigzag- and stripy-AFM phases in single-layer MnSe. For the dynamically stable four magnetic phases, predicted Raman spectra reveal that each phase exhibits distinctive vibrational features and can be distinguished from each other. In addition, the elastic constants indicate the mechanical stability of each magnetic phase in single-layer MnSe and reveal the soft nature of each phase. Moreover, electronic band dispersion calculations show the indirect band gap semiconducting nature with varying electronic band gap energies for all magnetic phases. Furthermore, the atomic orbital-based density of states reveals the existence of out-of-plane orbitals dominating the top valence states in zigzag- and stripy-AFM phases, giving rise to the localized states. The stability of different magnetic phases and their distinct vibrational and electronic properties make single-layer MnSe a promising candidate for nanoelectronic and spintronic applications.

A first principles study of structural, electronic, elastic, thermal and optical properties of SiZr and GeZr

In the present work, the full-potential linearized augmented plane wave method is implemented to study the structural, electronic, elastic, thermal, and optical properties of semiconductor-based cubic perovskite compounds of SiZr and GeZr. The magnetic phase stability calculations are performed to identify the most stable magnetic state. SiZr and GeZr are predicted to be stable in anti-ferromagnetic phase. The ground state properties such as lattice parameter, elastic constants, bulk modulus, and pressure derivative are calculated. From the band structure calculations, these compounds exhibit narrow band gaps, which are semiconducting in nature. From the values of bulk to shear modulus B/G ratio (Pugh’s ratio), the compounds are found to be ductile. The values of Poisson’s ratio and Zener’s anisotropic index suggest that these compounds show covalent bonding and weak isotropy. A larger Debye temperature implies that compounds have strong interatomic bonding, greater hardness, high melting temperature, and higher mechanical wave velocity. The optical properties such as optical conductivity, reflectivity, and absorption coefficient suggest that SiZr could be a more suitable compound for solar cell applications.

Investigation on effect of sintering temperature on structural, morphological and magnetic properties of pure and tin doped nickel ferrites for soft magnetic device applications

Based on the importance of the understanding of the ferrite material properties at high temperature conditions, the present authors made re-investigation for pure and tin doped nickel ferrite materials at sintering temperature conditions such as 900 to 1200°C with 100 deg interval. Crystallographic phase stability and grain size effects of pure and doped test samples with respect to temperature are evaluated by powder X-ray diffractometer (PXRD). Surface morphology and magnetic phase stabilities are details are examined by the scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Fortunately, 1200 deg/C sintered pure and tin doped title material showed the good crystalline nature and high statured saturation magnetization compared to other samples due to the re-crystallization effect taking place by the impact of sintering temperature. The triangle correlation of structural – morphological- magnetic properties is discussed.

Scrutinized the inherent spin half-metallicity and thermoelectric response of f-electron-based RbMO3 (M = Np, Pu) perovskites: a computational assessment

In the hunt for novel materials, we present self-consistent ab initio simulations of the structural stability, electronic profile, and transport properties of f-electron-based RbMO3 (M = Np, Pu) perovskites within the context of density functional theory. The structural stability and thermodynamic concerns are fixed by relaxing the crystal structure and computing the energy of formation, respectively. Furthermore, the decisive physical features of given materials have been outlined using the optimised lattice constant retrieved from structural optimizations. The ground state magnetic phase stability is ascertained by minimizing Birch Murnaghan's equation of state in distinct magnetic phases, upholding the ferromagnetic phase (FM) as the ground state magnetic phase, which is further backed by positive Curie Wiess constant values. To specify the electronic structure, a mix of the two approximations GGA and GGA + mBJ has been executed, both of which assert the half-metallic character, culminating in 100% spin polarisation at the Fermi level. The study of the magnetic moment and Curie temperature of each material has further been assessed in the present study. Apart from half-metallicity, the thermoelectric response of the present materials is quantified by exploring the chemical potential dependency of several transport parameters like Seebeck coefficient, electrical and thermal conductivity, power factor, etc. Moreover, the thermoelectric competence has been tested using a zT calculation, adapting values of 1.01 and 0.987 at 300 K for RbNpO3 and RbPuO3, respectively. The high electronic zT at encompassing temperatures uncovers the significant utility of these materials in both low-and high-temperature thermoelectric device applications. In essence, the comprehensive survey of these alloys could certainly open up their possibilities in spintronics, thermoelectric, and solid-state (RTG) device applications.

One-pot synthesis of iron oxides decorated bamboo hydrochar for lead and copper flash removal

A novel one-pot codeposition strategy was developed by employing bamboo hydrochar as precursors to fabricate magnetic porous char (MPC) with Fe 3 O 4 or α-Fe loading. The synthesized MPC with well dispersed magnetic phase and high thermal stability displayed excellent adsorption capacities and flash adsorption rate for Cu(II) and Pb(II). The batch sorption experiments showed that MPC had the best performance with Langmuir adsorption capacities as high as 125.06 mg/g for Cu(Ⅱ) and 153.85 mg/g for Pb(Ⅱ), respectively. More importantly, the short time of adsorption reaching 90 % equilibrium within 10 min was considerably beyond previous study. Also, a synergistic mechanism of the chemical complexation and physical adsorption for the higher adsorption capabilities and flash removal rate of the synthesized MPC was proposed. The regeneration investigation revealed that the sorption efficiencies remained at high level with above 92.4 % for Cu(II) and 94.1 % for Pb(II) after five cycles. Thus, the MPC were expected to be a promising candidate for high-efficient and rapid removal of heavy metal contaminants from wastewater in future practical utilization . • Highly porous and thermal stable magnetic biochar were synthesized by one-pot method. • The adsorption capacities were 125.06 mg/g for Cu(Ⅱ) and 153.85 mg/g for Pb(Ⅱ), respectively. • The adsorption reached 90 % of the adsorption equilibrium within 10 min. • The sorption efficiencies of regeneration remained above 92.4 % for Cu(II) and 94.1 % for Pb(II) after five cycles.

Shock wave recovery experiments on α-V2O5 nano-crystalline materials: A potential material for energy storage applications

Most of the functional materials fail to maintain their crystallographic sustainability at high-temperature and high-pressure conditions so that identifying materials of high stability in such atmosphere is essential for the actual requirement of the practical applications. In this framework, the shock wave recovery experiments have been performed on α -V2O5 to assess its crystallographic, electronic and magnetic phase stabilities with respect to the number of shock pulses such as 0, 50, 100 and 150 such that the results of phase stability have been evaluated by X-ray diffraction (XRD), Vibrational spectroscopy (Raman), optical spectroscopy (UV-DRS) and vibrating sample magnetometer (VSM). The observed shocked sample’s diffraction and spectroscopic results clearly demonstrate the formation of defective crystal structures with massive oxygen vacancies. Remarkably, the orange sample is turned into yellow while increasing the number of shock pulses. FE-SEM images show the significant changes in the surface morphology, particularly at 150 shocked conditions. In addition to that, the electrochemical analysis has been performed to extract the role on surface morphological changes and oxygen vacancies in the electrochemical properties such as electrical resistance and specific capacitance such that we find a rapid enhancement of specific capacitance at 150 shocked conditions than that of the control and other shocked conditions. Hence, we could suggest that shocked-V2O5 NPs can be effectively used for energy storage applications.

A comprehensive investigation of structural and magnetic phase stability, electronic, magnetic and thermoelectric properties of Co2FeZ (Z = Al, Ga, Si, Ge, S, Se and Te) Full Heusler alloys

A series of full Heusler (FH) alloys Co2FeZ (Z = Al, Ga, Si, Ge, S, Se and Te) have been investigated using density functional theory (DFT) with full potential-linearized augmented plane wave (FPLAPW) method within generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) functional. Most stable structures are determined by considering four different atomic arrangements i.e. L21-I/II (conventional) and XA-I/II (inverse) configurations. Stable magnetic phases like anti-ferromagnetic (AFM), nonmagnetic (NM) and ferromagnetic (FM) are evaluated and results revealed that FM phase is the most stable of all alloys. Spin band structures are calculated by applying GGA and GGA + mBJ approach. The results showed the half metallic nature of Co2FeAl and Co2FeGe alloys. The obtained band diagrams are compared with density of states (DOS) and revealed that the both Fe and Co atoms contributes maximum in total magnetic moment (MM). The calculated values of total magnetic moment (MT) of all compounds range from 4 to 6 μB and are in well agreement with the findings of Slater-Pauling Rule (SPR). Both alloys i.e. Co2FeAl and Co2FeGe showed 100% level of spin polarization (SP) at Fermi level. Mean field approximation (MFA) is employed to determine Curie temperature (Tc) and the values thus obtained are higher than room temperature. Furthermore, the thermoelectric parameters i.e. Seebeck coefficient (S) along with thermal (κ) and electrical (σ) conductivities for both Co2FeAl and Co2FeGe alloys are calculated and discussed in detail. The obtained results envisaged that the investigated alloys are suitable candidates for thermoelectric and spintronic applications.

Intrinsically High Magnetic Performance in Core–Shell Structural (Sm,Y)Fe12‐Based Permanent Magnets (Adv. Mater. 28/2022)

(Sm,Y)Fe12-Based Magnets In article number 2203503, Xuefeng Zhang, Wei Li, and co-workers demonstrate the construction of a core–shell structure (Sm-rich shell and Y-rich core) in a (Sm,Y)Fe12-based magnet via a spontaneous spinodal decomposition process, resulting in the synchronous enhancement of magnetic properties and phase stability in the optimized alloy. An innovative strategy is thus provided, which has important significance for the design of high-performance magnets.

Strain engineering of the magnetic anisotropy and magnetic moment in NdFeO3 epitaxial thin films

Strain engineering is a powerful mean for tuning the various functionalities of ABO3 perovskite oxide thin films. Rare-earth orthoferrite RFeO3 materials such as NdFeO3 (NFO) are of prime interest because of their intriguing magnetic properties as well as their technological potential applications especially as thin films. Here, using a large set of complementary and advanced techniques, we show that NFO epitaxial thin films, successfully grown by pulsed laser deposition on (001)-SrTiO3, show a strong magnetic anisotropy below a critical thickness tc of 54 nm, associated with the occurrence of structural modifications related to symmetry and domain pattern changes. By varying the tensile misfit strain through the decrease of film thickness below tc, the amplitudes of in and out-of-plane magnetization can be continuously tuned while their ratio stays constant. Furthermore, different low-temperature magnetic behaviors are evidenced for strained and relaxed films, suggesting that the strain-induced structural state impacts the magnetic phase stability.

Sustainable structural, morphological and magnetic properties of MgFe2O4 nanoparticles under dynamic shock wave exposure

In this article, the authors have explored the changes caused in structural, morphological and magnetic properties of magnesium ferrite nanoparticles (MgFe2O4 NPs) under dynamic shock wave exposure situations. Interestingly, the observed XRD and VSM results reveal that the MgFe2O4 NPs have outstanding crystallographic and magnetic phase stability against the impact of shock waves and found that the title NPs are having higher shock resistance than other potential materials such as TiO2, Co3O4 and ZnFe2O4 NPs.

Combined experimental and DFT studies of Co82Zr12V6-xBx melt-spun ribbons to investigate structure and magnetic properties

For the development of rare-earth free permanent magnets with better performance to cost ratio, V and B dopings were employed to enhance the hard magnetic properties of Zr-Co-V-B alloys. The effect of V and B microalloying additions on the magnetic properties, phase stability and microstructure of the metastable Co5Zr phase have been investigated with experimental measurements together with first principles based on the DFT (Density Functional Theory) calculations. This study also investigates the effects of annealing at different temperatures on the intrinsic and extrinsic magnetic properties of Co82Zr12V6-xBx melt-spun ribbons. Rapidly solidified Co82Zr12V6-xBx (x = 1, 2, 3) alloy ribbons were produced by melt-spinning. For as-spun Co82Zr12V6-xBx (x = 1, 2, 3) ribbons, the coercivityHcdecreases from 2.34 kOe to 0.008 kOe with an increasing × value from 1 to 3.The amorphous alloy ribbons were annealed in a vacuum furnace at a series of temperatures of 600 °C, 650 °C, 700 °C and 750 °C each for 30 min. The XRD analysis showed the presence of two soft magnetic phases (fcc-Co and Co23Zr6), accompanied with a hard phase Co5Zr in ribbons thus leading to the desired hard/soft structure and the amount of both (hard and soft) phases increased with the annealing temperature. Coercivity was found to increase upon annealing treatment. The phase stabilities of the Co82Zr12V6-xBx ribbons were calculated from the total energy by the DFT calculations in this work. The calculated magnetic anisotropy energies have been compared to that of experimental coercivity values. Annealed sample Co82Zr12V5B1 showed the maximum coercivity value of 3.58 kOe due to the formation of a high volume fraction of hard magnetic phase (Co5Zr) and evenly distributed finer grains throughout the matrix. However, annealing under the same conditions resulted in lower coercivity of about 0.088 kOe and 1.61 kOe for Co82Zr12V3B3 and Co82Zr12V4B2 samples, respectively. Although sample Co82Zr12V4B2 exhibited higher remanence (42.80 emu/g) and maximum magnetization value with the applied field of 17 kOe (i.e. M17 = 77.70 emu/g) compared to Co82Zr12V3B3 sample.

Band topology resisted spin-state evolution of perovskite ACoO[formula omitted] (A = Ca, Sr) under pressure

There has been a debate on the theoretical explaining of the spin states in the perovskite ACoO3, especially SrCoO3. The aim of this work was to investigate the magnetic phase stability and to study the evolution of the spin states of the cubic perovskite ACoO3 (A = Ca, Sr) under pressure up to 40 GPa by using the density functional theory and the Hubbard +U parameters (DFT+U). Both CaCoO3 and SrCoO3 exhibit the ferromagnetic and metallic properties under pressure. Our results of the total magnetization and the net-spin density corroborate that a change of the magnetic behaviors on ACoO3 mostly depends on the value of Co-O bond length (dCo−O). We discovered a down-stepwise evolution of the total magnetization as a relationship with the dCo−O decreasing. This stepwise behavior occurs prior to the spin crossover from intermediate spin (IS) state to low spin (LS) state. The total magnetization values non-monotonically decreased from 2.49 to 2.16 μB/f.u. between the dCo−O = 1.88 and 1.80 Å. From our evidence, we indicated that the spin state of Co-3d states resembles the d7L̲2 character with t2g3↑,2↓eg2−x↑,x↓L̲2 state, where x≈0.5 and L̲ denotes the oxygen’s charge transfer from the oxygen ligands. Indeed, we discovered that the stepwise evolution of the total magnetization is associated with the changes in the band topology of the Co-3deg∗ band.

Tuning the magnetic phase diagram of Ni-Mn-Ga by Cr and Co substitution

Ni-Mn-based Heusler alloys have a high technical potential related to a large change of magnetization at the structural phase transition. These alloys show a subtle dependence of magnetic properties and structural phase stability on composition and substitution by 3d elements and although they have been extensively investigated, there are still ambiguities in the published results and their interpretation. To shed light on the large spread of reported properties, we perform a comprehensive study by means of density functional theory calculations. We focus on Cr and Co co-substitution whose benefit has been predicted previously for the expensive Ni-Mn-In-based alloy and study the more abundant iso-electronic counterpart Ni-Mn-Ga. We observe that substituting Ni partially by Co and/or Cr enhances the magnetization of the Heusler alloy and at the same time reduces the structural transition temperature. Thereby, Cr turns out to be more efficient to stabilize the ferromagnetic alignment of the Mn spins by strong antiferromagnetic interactions between Mn and Cr atoms. In a second step, we study Cr on the other sublattices and observe that an increase in the structural transition temperature is possible, but depends critically on the short-range order of Mn and Cr atoms. Based on our results, we are able to estimate composition dependent magnetic phase diagrams. In particular, we demonstrate that neither the atomic configuration with the lowest energy nor the results based on the coherent potential approximation are representative for materials with a homogeneous distribution of atoms and we also predict a simple method for fast screening of different concentrations which can be viewed as a blueprint for the study of high entropy alloys. Our results help to explain the large variation of experimentally found materials properties.

Strain-Induced Magnetic Transitions in SrMO2.5 (M = Mn, Fe) Thin Films with Ordered Oxygen Vacancies.

We examine the epitaxial-strain-induced phase transitions in thin films of perovskite-derived SrMnO2.5 and SrFeO2.5 exhibiting ordered oxygen vacancies (OOVs). We find that SrMnO2.5 hosts multiple magnetic transitions to other ordered states, including antiferromagnetic (AFM) and ferromagnetic (FM) orders of E*-AFM, C-AFM, and FM types depending on the compressive or tensile strain state. In contrast, no magnetic transitions occur in thin-film SrFeO2.5 (G-AFM to FM), whereas its bulk phase exhibits a hydrostatic pressure-induced AFM-to-FM transition. We explain the origin of these dependencies on the transition-metal configuration, that is, d4 Mn versus d5 Fe, and the relative orientation of the OOVs in the Ca2Mn2O5-type structure with respect to the epitaxial interface. We find that the magnetic phase stability can be predicted by using exchange striction arguments, with FM (AFM) spin interactions preferring longer (shorter) Mn-O bonds in the square pyramidal MnO5 unit comprising SrMnO2.5. Because the Mn-O bond lengths directly shrink or elongate to accommodate the applied stress without considerable polyhedral rotations, we show that compressive and tensile strain tune the unit cell structure to favor different combinations of exchange interactions that stabilize the various magnetic spin orders. Our study shows that the strong coupling between the OOV structure and spin orders with epitaxial strain is a promising route to achieve picoscale control of functional electronic and magnetic responses in complex oxide thin films.