Giant Piezomagnetism in Mn3NiN Boldrin, David; Mihai, Andrei P; Zou, Bin ...
ACS applied materials & interfaces,
06/2018, Volume:
10, Issue:
22
Journal Article
Peer reviewed
Open access
Controlling magnetism with electric field directly or through strain-driven piezoelectric coupling remains a key goal of spintronics. Here, we demonstrate that giant piezomagnetism, a linear ...magneto-mechanic coupling effect, is manifest in antiperovskite Mn3NiN, facilitated by its geometrically frustrated antiferromagnetism opening the possibility of new memory device concepts. Films of Mn3NiN with intrinsic biaxial strains of ±0.25% result in Néel transition shifts up to 60 K and magnetization changes consistent with theory. Films grown on BaTiO3 display a striking magnetization jump in response to uniaxial strain from the intrinsic BaTiO3 structural transition, with an inferred 44% strain coupling efficiency and a magnetoelectric coefficient α (where α = dB/dE) of 0.018 G cm/V. The latter agrees with the 1000-fold increase over Cr2O3 predicted by theory. Overall, our observations pave the way for further research into the broader family of Mn-based antiperovskites where yet larger piezomagnetic effects are predicted to occur at room temperature.
The urgent need for sustainable construction that corresponds to the three pillars of sustainable development is obvious and continuously requires innovative solutions. Cementitious composites with ...TiO2 nanoparticles (NT) addition show potential due to their improved durability, physico–mechanical characteristics, and self-cleaning capacity. This study aimed to evaluate the influence of NT on cementitious composites by comparing those with 2%–5% nanoparticles with a similar control sample without nanoparticles, as well as an analysis of cost growth. The experimental results showed an increase in bulk density of the material (4.7%–7.4%), reduction in large pore sizes by min. 12.5%, together with an increase in cumulative volume and cumulative specific surface area of small pore sizes, indicating densification of the material, also supported by SEM, EDS, and XRD analyses indicating acceleration of cement hydration processes with formation of specific products. The changes at microstructural level support the experimental results obtained at macrostructural level, i.e., modest but existent increases in flexural strength (0.6%–7.9%) and compressive strength (0.2%–2.6%) or more significant improvements in abrasion resistance (8.2%–58%) and reduction in water absorption coefficient (37.5%–81.3%). Following the cost–benefit analysis, it was concluded that, for the example case considered of a pedestrian pavement with a surface area of 100 m2, using 100 mm thick slabs, if these slabs were to be made with two layers, the lower layer made of cementitious composite as a reference and the upper layer with a thickness of 10 mm made of cementitious composite with 3% NT or 4% NT, the increase in cost would be acceptable, representing less than 15% compared to the cost for the exclusive use of cementitious composite without NT.
Giant Piezomagnetism in Mn 3 NiN Boldrin, David; Mihai, Andrei P; Zou, Bin ...
ACS applied materials & interfaces,
2018-Jun-06, 2018-06-06, Volume:
10, Issue:
22
Journal Article
Peer reviewed
Controlling magnetism with electric field directly or through strain-driven piezoelectric coupling remains a key goal of spintronics. Here, we demonstrate that giant piezomagnetism, a linear ...magneto-mechanic coupling effect, is manifest in antiperovskite Mn
NiN, facilitated by its geometrically frustrated antiferromagnetism opening the possibility of new memory device concepts. Films of Mn
NiN with intrinsic biaxial strains of ±0.25% result in Néel transition shifts up to 60 K and magnetization changes consistent with theory. Films grown on BaTiO
display a striking magnetization jump in response to uniaxial strain from the intrinsic BaTiO
structural transition, with an inferred 44% strain coupling efficiency and a magnetoelectric coefficient α (where α = d B/d E) of 0.018 G cm/V. The latter agrees with the 1000-fold increase over Cr
O
predicted by theory. Overall, our observations pave the way for further research into the broader family of Mn-based antiperovskites where yet larger piezomagnetic effects are predicted to occur at room temperature.
Soft magnetic composite of Fe/Fe 3 O 4 type was synthesized by mechanical milling and reactive sintering starting from a mixture of Fe and Fe 2 O 3 commercial powders. During mechanical milling, the ...Fe and Fe 2 O 3 phases start to react after 120 min. A composite powder of Fe/Fe 2 O 3 type results after 60 and 120 min of milling. The composite powder obtained by milling was pressed in toroidal shape at 100 up to 300 MPa. The green composite compacts (Fe/Fe 2 O 3 ) were sintered at 1100 °C for 6 h, resulting in Fe/Fe 3 O 4 like sintered composite compacts having an amount of FeO phase. The microstructure analysis shows an iron matrix that embeds iron oxide clusters. The magnetic measurements in dc current indicate the positive influence of the increased applied pressure on the magnetic permeability and saturation induction characteristics. The investigations in dc revealed that the milling time has almost no influence on the magnetic characteristics of the sintered composite compacts. ac investigations showed that the magnetic permeability decreases upon increasing the testing frequency. The total losses increase significantly by increasing the frequency due to the excessive increase in eddy currents at higher frequencies.
Nanocrystalline Supermalloy powders were obtained by wet milling in argon atmosphere. As process control agent the C 6 H 6 was used. Several milling times have been used ranging from 2 up to 20 h. ...The formation of the alloy was evidenced by X-ray diffraction (XRD). An annealing at 623 K for 4 h was applied in order to remove the internal stresses and to finish the solid state reaction. A typical crystallite size of 11-12 nm has been obtained after 20 h of wet milling. The magnetic measurements have been performed in a magnetic field up to 8 T at 300 K. A decrease of magnetization is observed upon increasing the milling time due both to the defects induced during the milling and to adsorbed benzene on the particles surface. Differential scanning calorimetry (DSC) curves show the exothermic peaks correlated with the presence of the C 6 H 6 on the powder particles. The benzene and the internal stresses and crystalline defects are eliminated and an increase of magnetization with milling time can be observed for samples annealed at 623 K for 4 h.
The urgent need for sustainable construction that corresponds to the three pillars of sustainable development is obvious and continuously requires innovative solutions. Cementitious composites with ...TiOsub.2 nanoparticles (NT) addition show potential due to their improved durability, physico–mechanical characteristics, and self-cleaning capacity. This study aimed to evaluate the influence of NT on cementitious composites by comparing those with 2%–5% nanoparticles with a similar control sample without nanoparticles, as well as an analysis of cost growth. The experimental results showed an increase in bulk density of the material (4.7%–7.4%), reduction in large pore sizes by min. 12.5%, together with an increase in cumulative volume and cumulative specific surface area of small pore sizes, indicating densification of the material, also supported by SEM, EDS, and XRD analyses indicating acceleration of cement hydration processes with formation of specific products. The changes at microstructural level support the experimental results obtained at macrostructural level, i.e., modest but existent increases in flexural strength (0.6%–7.9%) and compressive strength (0.2%–2.6%) or more significant improvements in abrasion resistance (8.2%–58%) and reduction in water absorption coefficient (37.5%–81.3%). Following the cost–benefit analysis, it was concluded that, for the example case considered of a pedestrian pavement with a surface area of 100 msup.2, using 100 mm thick slabs, if these slabs were to be made with two layers, the lower layer made of cementitious composite as a reference and the upper layer with a thickness of 10 mm made of cementitious composite with 3% NT or 4% NT, the increase in cost would be acceptable, representing less than 15% compared to the cost for the exclusive use of cementitious composite without NT.
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