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The magnetic phase diagram of Sr[Formula: see text]Ca[Formula: see text]Co[Formula: see text]P[Formula: see text] as a function of hydrostatic pressure and temperature is investigated by means of high pressure muon spin rotation, relaxation and resonance ([Formula: see text]SR). The weak pressure dependence for the [Formula: see text] compounds suggests that the rich phase diagram of Sr[Formula: see text]Ca[Formula: see text]Co[Formula: see text]P[Formula: see text] as a function of x at ambient pressure may not solely be attributed to chemical pressure effects. The [Formula: see text] compound on the other hand reveals a high pressure dependence, where the long range magnetic order is fully suppressed at [Formula: see text] kbar, which seem to be a first order transition. In addition, an intermediate phase consisting of magnetic domains is formed above [Formula: see text] kbar where they co-exist with a magnetically disordered state. These domains are likely to be ferromagnetic islands (FMI) and consist of an high- (FMI-[Formula: see text]) and low-temperature (FMI-[Formula: see text]) region, respectively, separated by a phase boundary at [Formula: see text] K. This kind of co-existence is unusual and is originating from a coupling between lattice and magnetic degrees of freedoms.

Novel amorphous iron hydrides (AIHs) are synthesized for the first time under ambient conditions by employing novel “quiescent reaction”, without stirring for mixing solutions, during a conventional aqueous reduction-precipitation process. The kind and morphology of AIHs are dependent on the processing condition, where two types are found, with one form consisting of a tangle of uniform nanowires and the other being granular in nature. Both AIHs undergo transformation to crystalline α-Fe by heat treatment at 600 °C. The nanowire AIH exhibits the hydrogen content of 0.10 wt%, while the granular AIH of 0.22 wt%. Their magnetic and thermal properties are accordingly different, and the non-diffusive hydrogen contributes to stability of AIHs. It is strongly suggested that, by use of quiescent reaction, iron-hydrogen clusters are formed and preserved at an early stage of precipitation reaction, and subsequently aggregated into novel AIHs, preventing α-Fe crystallization. Hence, the AIHs would be categorized as metastable hydrides stabilized with iron-hydrogen clusters. In addition, newly discovered quiescent reaction in aqueous solution, from which unprecedented AIHs are derived, sheds new light on fundamental and essential aqueous reaction.

Spin Seebeck effect (SSE), the generation of spin current from heat, has been extensively studied in a large variety of magnetic materials, including ferromagnets, antiferromagnets, paramagnets, and quantum spin liquids. In this paper, we report the study of the SSE in the single crystalline Pb2V3O9, a spin-gapped quantum magnet candidate with quasi-one-dimensional spin-1/2 chain. Detailed temperature and magnetic field dependences of the SSE are investigated, and the temperature-dependent critical magnetic fields show a strong correlation to the Bose-Einstein condensation phase of the quantum magnet Pb2V3O9. This work shows the potential of using spin current as a probe to study the spin correlation and phase transition properties in quantum magnets., Comment: 15 pages, 4 figures

The magnetic phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ as a function of hydrostatic pressure and temperature is investigated by means of high pressure muon spin rotation, relaxation and resonance ($\mu^+$SR). The weak pressure dependence for the $x\neq1$ compounds suggests that the rich phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ as a function of $x$ at ambient pressure may not only be attributed to solely chemical pressure effects. The $x=1$ compound on the other hand reveals a high pressure dependence, where the long range magnetic order is fully suppressed at $p_{\rm c2}\approx9.8$~kbar, which seem to be a first order transition. In addition, an intermediate phase consisting of dilute ferromagnetic islands (FMI) is formed above $p_{\rm c1}\approx8$~kbar where they co-exist with a magnetically disordered state. Moreover, such FMI phase seems to consist of an high- (FMI-\textcircled{\small{1}}) and low-temperature (FMI-\textcircled{\small{2}}) region, respectively, separated by a phase boundary at $T_{\rm i}\approx20$~K., Comment: 10 pages, 8 figures

The ferromagnetic (FM) nature of the metallic LaCo$_2$P$_2$ was investigated with the positive muon spin rotation, relaxation and resonance ($\mu^+$SR) technique. Transverse and zero field $\mu^+$SR measurements revealed that the compound enters a long range FM ground state at $T_{\rm C}=130.91(65)$~K, consistent with previous studies. Based on the reported FM structure, the internal magnetic field was computed at the muon sites, which were predicted with first principles calculations. The computed result agree well with the experimental data. Moreover, although LaCo$_2$P$_2$ is a paramagnet at higher temperatures $T>160$~K, it enters a short range ordered (SRO) magnetic phase for $T_{\rm C}, Comment: 9 pages, 7 figures

To enhance the magnetic property as well as to get the magnetic ordering in Sm2O3 which is a good dielectric material, Co-ion is substituted by a chemical route. Rietveld analysis of x-ray diffraction (XRD) pattern of the sample (Sm1.90Co0.10O3) suggests that all the dopants are properly substituted in the monoclinic lattice of Sm2O3. XRD analysis and Raman spectroscopic observation ruled out the segregation of Co-cluster or formation of any impurity in Sm1.90Co0.10O3. Magnetic susceptibility ( $$ \chi $$ ) of the sample measured in the range of 300–14 K by Faraday balance indicates the paramagnetic behavior down to 50 K, below which non-linear magnetic nature with ferromagnetic ordering is found. The onset of ferromagnetism in a doped dielectric host is investigated in detail by observing magnetization versus magnetic field (M–H) data and magnetization versus temperature (M–T) curves recorded under zero field cooled and field cooled conditions. All the data extracted from the magnetic measurements are analyzed to yield useful information of the newly developed diluted magnetic dielectric.

Anomalous successive structural transitions in layered 1T-CrSe2 with an unusual Cr4+ valency were investigated by synchrotron X-ray diffraction. 1T-CrSe2 exhibits dramatic structural changes in in- ...

Nanocrystalline samples of undoped dysprosium oxide (Dy2O3) and Ni2+ doped Dy2O3 (Dy1.90Ni0.10O3-δ/DNO) are prepared by co-precipitation method. X-ray diffraction (XRD) analysis by Maud software confirmed the desired crystallographic phase of both samples and also the substitution of Ni2+ ion in Dy2O3 lattice. Absence of impurity is confirmed from Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and high resolution transmission electron microscope (HRTEM) analysis. Magnetization vs. field (M-H) loop of DNO recorded at 5 and 10 K shows clear hysteresis loop with magnetization ∼138.71 emu/g at 5 K and ∼121.52 emu/g at 10 K with applied magnetic field of 5 T. The deviation of inverse susceptibility vs. temperature curve from Curie-Weiss fitting below ∼30 K and also the deviation of initial magnetization data of M-H loop recorded at 30 K from linear fitting suggests that the DNO is in mixed paramagnetic and ferromagnetic phase at and below ∼30 K. Defect mediated ferromagnetic ordering found in DNO at low temperature, is analyzed by bound magnetic polaron model.

This chapter reviews the history of magnetism, which is one of the main streams of solid-state physics and quantum physics, and developments of itinerant-electron magnetism and exotic superconductivity in terms of spin fluctuations are discussed from theoretical and experimental points of view. Spin-fluctuation theories beyond mean-field approximations are important to explain static magnetic properties as well as the dynamical properties of itinerant magnets. It was found that electron-pair formation due to magnetic spin fluctuations can be realized in exotic superconductors. Problems in itinerant-electron systems continue to attract our interest.

An $A$-type antiferromagnet, ${\mathrm{NaNiO}}_{2}$, was examined by means of positive muon spin rotation and relaxation (${\ensuremath{\mu}}^{+}\mathrm{SR}$) measurements and first-principles calculations based on a density functional theory (DFT). Below ${T}_{\mathrm{N}}=20$ K, a clear muon spin precession signal was observed in the ${\ensuremath{\mu}}^{+}\mathrm{SR}$ time spectrum recorded under zero field, due to the formation of a static internal magnetic field. The microscopic origin of such an internal field was computed as a sum of dipolar and hyperfine contact fields at the site (0.624, 0, 0.854), where both the muon site and the local spin density at such a site were predicted with DFT calculations. While the computed values were consistent with experimentally obtained ones, in both the antiferromagnetic and the paramagnetic states, the contribution of the hyperfine contact field was shown to be insignificant even below ${T}_{\mathrm{N}}$. Finally, measurements at higher temperatures signified thermally activated Na-ion diffusion with ${E}_{\mathrm{a}}=50(20)$ meV and ${D}_{\mathrm{Na}}(300\phantom{\rule{0.16em}{0ex}}\mathrm{K})=8.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{2}$/s, commonly observed in layered-type compounds.

Nanocrystalline ZnO and Yb-doped ZnO (Zn0.98Yb0.02O) are prepared by simple co-precipitation method. The pure crystallographic phases of ZnO and Zn0.98Yb0.02O are confirmed by Rietveld analyses of XRD patterns. Raman and photoluminescence spectra recorded at room temperature (RT) indicates that lattice defects and oxygen vacancy in Zn0.98Yb0.02O is more than that of ZnO. Magnetic measurements of ZnO and Zn0.98Yb0.02O are carried out from 300 to 5 K. Ferromagnetic ordering is observed in Zn0.98Yb0.02O at RT and the strength of the ordering increases with the lowering of temperature. Ferromagnetism of Zn0.98Yb0.02O is attributed to the oxygen vacancy introduced by annealing in vacuum. Magnetization vs. temperature curve is well fitted by the combination of 3D spin wave and Curie-Weiss law, which suggest simultaneous presence of para- and ferro-magnetic phases in Zn0.98Yb0.02O. Ferromagnetic ordering is successfully explained by vacancy mediated bound-magnetic polaron model.

Significance A unifying mechanism for the origin of ferromagnetism which takes into account both well-known and polar extreme theories, namely, the localized- and itinerant-electron regimes, remains a longstanding mystery. Here, we study a particularly interesting system of FeGa 3− y Ge y , within which the magnetic orderings can be adjusted by the Ge-electron filling control, turning from itinerancy to adequate localized through a ferromagnetic quantum critical transition with increasing y . By involving the effects of the spin fluctuations in general, the theoretical estimations of the magnetic properties at the intermediate state of magnetic orderings formulated in terms of the correlation between itinerancy electrons and the spin fluctuations are in quantitative agreements with experimental observations. Our analysis shows a potential universality to all itinerant ferromagnets.

The physical properties of novel cluster-based triangular lattice antiferromagnets Na3 A2 (MoO4 )2 Mo3 O8 (A=In, Sc), synthesized through a topochemical Na-intercalation to nonmagnetic Na2 A2 (MoO4 )2 Mo3 O8 , are reported. The S=1/2 [Mo3 ]11+ clusters form a regular triangular lattice, which gives the magnetic system a strong geometrical spin frustration effect. Despite the strong antiferromagnetic couplings among [Mo3 ]11+ clusters, they show no long-range magnetic orderings down to 0.5 K with the finite residual magnetic entropy. The ground states of Na3 A2 (MoO4 )2 Mo3 O8 have been characterized as a quantum spin liquid, owing to the strong spin frustration of cluster spins on the triangular lattice.

We grew large single crystals of the cluster magnet Nb3Cl8 with a magnetic triangular lattice and investigated its magnetic properties and crystal structure. In Nb3Cl8, the [Nb3]8+ cluster has a single unpaired spin, making it an S = 1/2 triangular lattice anti-ferromagnet. At low temperatures, Nb3Cl8 exhibits a magnetic-nonmagnetic phase transition driven by a charge disproportionation, in which the paramagnetic [Nb3]8+ clusters transform into alternating layers of nonmagnetic [Nb3]7+ and [Nb3]9+ clusters. The observed exotic phenomenon with the strong correlation between the magnetism and structure are based on the nature of the cluster magnetism.

We investigated the magnetic properties of the ilmenite-type manganates $\mathrm{MgMn}{\mathrm{O}}_{3}$ and $\mathrm{ZnMn}{\mathrm{O}}_{3}$, both of which are composed of a honeycomb lattice of magnetic $\mathrm{M}{\mathrm{n}}^{4+}$ ions. Both compounds show antiferromagnetic order with weak ferromagnetic moments. In particular, $\mathrm{MgMn}{\mathrm{O}}_{3}$ exhibits a magnetization ``reversal'' behavior which can be described by the $N$-type ferrimagnetism in the N\'eel's classification. The relationship between the magnetic properties and the crystal and magnetic structures probed by the neutron diffraction experiments indicates that the two honeycomb lattice magnets have different ${J}_{1}\ensuremath{-}{J}_{2}$ parameter sets, placing them in the distinct regions in the phase diagram; both nearest neighbor (NN) and next nearest neighbor (NNN) exchange interactions are antiferromagnetic in $\mathrm{MgMn}{\mathrm{O}}_{3}$, while NN and NNN interactions become ferromagnetic and antiferromagnet, respectively, in $\mathrm{ZnMn}{\mathrm{O}}_{3}$.

We synthesized a kagome fluoride ${\mathrm{Cs}}_{2}{\mathrm{LiTi}}_{3}{\mathrm{F}}_{12}$ with $S=1/2$ spins, and studied magnetic properties of the compound. The temperature dependence of the magnetic susceptibility indicates that it has dominant antiferromagnetic interactions and that it has no magnetic order down to 2 K. We found two magnetization plateaus in its magnetization process approximately at 1/3 and 0.8 ${\ensuremath{\mu}}_{\mathrm{B}}$ per Ti. The monoclinic crystal structure gives four inequivalent nearest-neighbor exchange interactions. Our density functional theory calculations suggest that three of them are antiferromagnetic and one of them is weakly ferromagnetic, resulting in a magnetic system composed of antiferromagnetically coupled linear chains and $\mathrm{\ensuremath{\Delta}}$ chains. This explains the observed suppression of magnetic order. Numerical diagonalization gives a magnetization curve in good agreement with the experimental results.

We have studied a mosaic of 1T-CrSe

We have studied a mosaic of 1T-CrSe$_2$ single crystals using $\beta$-detected nuclear magnetic resonance of $^{8}$Li from 4 to 300 K. We identify two broad resonances that show no evidence of quadrupolar splitting, indicating two magnetically distinct environments for the implanted ion. We observe stretched exponential spin lattice relaxation and a corresponding rate ($1/T_1$) that increases monotonically above 200 K, consistent with the onset of ionic diffusion. A pronounced maximum in $1/T_1$ is observed at the low temperature magnetic transition near 20 K. Between these limits, $1/T_1$ instead exhibits a broad minimum with a remarkable absence of strong features in the vicinity of structural and magnetic transitions between 150 and 200 K. Together, the results suggest $^{8}$Li$^{+}$ site occupation within the van der Waals gap between CrSe$_2$ trilayers. Possible origins of the two environments are discussed.

Anomalous successive structural transitions in layered 1

To enhance the magnetoelectric property of GaFeO 3 (GFO), Al 3+ doped samples (Al x Ga (1−x) FeO 3 , x=0.05, 0.10 and 0.20) are prepared by the sol-gel technique. Crystallographic phases of the samples are confirmed by X-ray diffractograms. Morphology, average size of nanoparticles including the distribution of sizes are obtained from the results of field emission scanning electron microscopy and high-resolution transmission electron microscopy. Distribution of blocking temperatures and magnetocrystalline anisotropy are determined from the analyses of the observed magnetic hysteresis loops and thermal variation of magnetization curve under zero field cooled and field cooled conditions. Variations of dielectric constant and dielectric loss with frequency show the dispersion in the low frequency region. Ferroelectric orderings have been improved in the doped samples compared to that of GFO. Polarization vs. electric field loops recorded at room temperature indicate that. Magnetic field dependent dielectric constant and negative magneto-capacitance co-efficient of the samples measured at room temperature confirmed that all the samples are multiferroic. Raman spectra and their analyses provide a greater insight into the phase purity and physical properties of the samples. Simultaneous enhancement in magnetic and electric polarizations together with the presence of magneto-electric coupling in the doped samples may enhance the quality of applications in devices.

The magnetic phase transition, optical and dielectric properties of nanocrystalline Tm3+-doped zinc oxide (Zn0.95Tm0.05O), prepared by the co-precipitation method, were determined for the first time. The oxygen vacancy of the as prepared sample was enhanced by annealing at 200 °C for 6 h in an argon atmosphere. The formation of defects/oxygen vacancy is reflected in the Raman, FTIR and PL spectral analyses of the doped sample. Paramagnetic to ferromagnetic phase transition of Zn0.95Tm0.05O was observed at and below ∼30 K. The onset of ordering is successfully explained by the vacancy assisted bound-magnetic-polaron (BMP) model. The results of dielectric measurements suggest that the dielectric response of Zn0.95Tm0.05O is significantly enhanced, compared to that of pristine ZnO, and this is due to the presence of large amounts of oxygen vacancies, and the nanostructure of the sample.

We have investigated the structural and magnetic properties of $S=3/2\phantom{\rule{4pt}{0ex}}{\mathrm{Cr}}^{3+}$ Heisenberg-like kagome lattice antiferromagnets ${\mathrm{Cs}}_{2}{\mathrm{K}}_{}{\mathrm{Cr}}_{3}{\mathrm{F}}_{12}$ and ${\mathrm{Cs}}_{2}{\mathrm{Na}}_{}{\mathrm{Cr}}_{3}{\mathrm{F}}_{12}$ using single crystals. Each compound has a slightly distorted kagome lattice, although the space groups differ for the two compounds. The magnetic data suggest that each compound exhibits the formation of antiferromagnetic ordering with in-plane-spin canting approximately below 6 K. The in-plane coplanar structures are clearly different from disordered ground states of the isostructural ${\mathrm{Ti}}^{3+}$ compounds and out-of-plane coplanar structures of the ${\mathrm{V}}^{3+}$ compounds, which is mainly caused by the differences in the strength of quantum fluctuation and the strength of magnetic anisotropy for these three spin systems. In contrast, as well as the ${\mathrm{Ti}}^{3+}$ and ${\mathrm{V}}^{3+}$ compounds, the magnetization curves show 1/3-magnetization-plateaulike anomalies.

We have successfully synthesized the novel antiferromagnets with Ir$^{4+}$ honeycomb lattice ZnIrO$_3$ and MgIrO$_3$ and investigated their magnetic and thermodynamic properties. The two iridates are isomorphic but exhibit qualitatively different magnetic properties. ZnIrO$_3$ shows antiferromagnetic ordering below 46.6 K, whereas MgIrO$_3$ displays weak ferromagnetic behavior below 31.8 K owing to formation of a canted antiferromagnetic ordering. The measurement of magnetic susceptibility with using an oriented powder sample revealed the presence of an XY-like magnetic anisotropy and a tilting magnetic structure which is possibly stabilized by the Kitaev interaction. Moreover, magnetization curves of MgIrO3 and ZnIrO3 up to 60 T show different behaviors, demonstrating that each magnetic ground state is different with each other. We discuss the difference in the ground state between MgIrO$_3$ and ZnIrO$_3$ from the viewpoint a magnetic model consisting of the Kitaev and Dzyaloshinskii-Moriya interactions with the spin frustration effect on the honeycomb lattice.

The physical properties of the mixed-valent iron oxide $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{NaFe}}_{2}{\mathrm{O}}_{3}$ were investigated by means of synchrotron radiation x-ray diffraction, magnetization, electrical resistivity, differential scanning calorimetry, $^{23}\mathrm{Na}$ NMR, and $^{57}\mathrm{Fe}\phantom{\rule{4pt}{0ex}}\mathrm{M}\stackrel{\ifmmode \ddot{}\else \"{}\fi{}}{\mathrm{o}}\mathrm{ssbauer}$ measurements. This compound has double triangular layers consisting of almost perfect regular ${\mathrm{Fe}}_{4}$ tetrahedra, which suggests geometrical frustration. We found that this compound exhibits an electrostatically unstable double-stripe-type charge ordering, which is stabilized by the cooperative compression of ${\mathrm{Fe}}^{3+}{\mathrm{O}}_{6}$ octahedra, owing to a valence change and ${\mathrm{Fe}}^{2+}{\mathrm{O}}_{6}$ octahedra due to Jahn-Teller distortion. Our results indicate the importance of electron-phonon coupling for charge ordering in the region of strong charge frustration.

A unifying mechanism for the origin of ferromagnetism which takes into account both well-known and polar extreme theories, namely, the localized- and itinerant-electron regimes, remains a longstanding mystery. Here, we study a particularly interesting system of FeGa3−yGey, within which the magnetic orderings can be adjusted by the Ge-electron filling control, turning from itinerancy to adequate localized through a ferromagnetic quantum critical transition with increasing y. By involving the effects of the spin fluctuations in general, the theoretical estimations of the magnetic properties at the intermediate state of magnetic orderings formulated in terms of the correlation between itinerancy electrons and the spin fluctuations are in quantitative agreements with experimental observations. Our analysis shows a potential universality to all itinerant ferromagnets.

QC 20211215

QC 20211124

In this chapter, I will explain what the absolute zero and the absolute emptiness (vacuum/void ) are in the fields of quantum physics and chemistry. At first one likely believes that there is nothing—no particles at all—in the vacuum state. Is it correct? The importance of this question even extends to other fields, including philosophy and religion. To answer this question, we must examine the history of modern physical sciences since the early 20th century. Here, I will discuss quantum physics and chemistry, especially solid-state quantum physics and chemistry .

The magnetic properties of a melt-spun Cu 60 Au 35 Fe 5 alloy are examined by X-ray diffraction (XRD), magnetic measurements, and transmission electron microscopy (TEM). The XRD pattern of an as-spun sample indicates the formation of a solid solution of Cu and Au with no Fe phase, whereas that of the annealed sample (773 K × 36 ks) shows a small amount of the α-Fe phase because the Fe atoms precipitate during annealing. TEM observations and EDX analysis of the as-spun sample show no distinct Fe-rich domains, implying that some Fe atoms are dissolved in the matrix, and others form very fine magnetic clusters. Moreover, magnetic measurements indicate the presence of magnetic clusters and isolated Fe atoms. The AC magnetic susceptibilities show that the as-spun sample has a sharp cusp around 20 K, which is characteristic of spin glass behavior. The simulations of the M – H curves of the as-spun sample measured at 77 and 300 K, show that most Fe atoms are dissolved in the matrix as isolated atoms, not as clusters. Additionally, the calculated rate of clustering in the as-spun sample tends to decrease with temperature, suggesting that the magnetic exchange interactions are weak.

Soft X-ray micro-ARPES measurements have successfully been applied to band mapping of the strongly correlated metallic V2O3., Soft X-ray angle-resolved photoemission has been performed for metallic V2O3. By combining a microfocus beam (40 µm × 65 µm) and micro-positioning techniques with a long-working-distance microscope, it has been possible to observe band dispersions from tiny cleavage surfaces with a typical size of several tens of µm. The photoemission spectra show a clear position dependence, reflecting the morphology of the cleaved sample surface. By selecting high-quality flat regions on the sample surface, it has been possible to perform band mapping using both photon-energy and polar-angle dependences, opening the door to three-dimensional angle-resolved photoemission spectroscopy for typical three-dimensional correlated materials where large cleavage planes are rarely obtained.

The magnetic properties of a melt-spun Fe-dilute Cu 60 Ag 35 Fe 5 alloy are examined by X-ray diffraction, magnetic measurements, and transmission electron microscopy (TEM). The X-ray diffraction patterns show that the as-spun and annealed (773 K×36 ks) samples contain Cu and Ag phases and no Fe phases; thus, most Fe atoms are dispersed as clusters. Magnetic measurements indicate that the as-spun and annealed samples exhibit superparamagnetic behavior at 300 K, whereas ferromagnetic and superparamagnetic behaviors coexist at 4.2 K. The magnetic moments of small clusters at 300 K are determined by the nonlinear least squares method as 5148 and 4671 μ B for as-spun and annealed samples, respectively, whereas those at 300 K are experimentally determined as 3500 and 3200 μ B . This decrease in magnetic moments may imply the formation of anti-ferromagnetic coupling by annealing. TEM observation of the melt-spun sample suggests that there are three regions with different compositions: Cu-rich, Ag-rich, and Fe-rich with no precipitation in the matrix. In addition, these regions have obscure interfaces. The magnetic clusters are attributed to the Fe-rich regions.

In order to elucidate the dependence of the magnetic ground state on the Ca content (x) in Sr1-xCaxCo2P2 (0 ≤x ≤1, ThCr2Si2-type structure), we have performed muon spin rotation− and relaxation (μ+SR) experiments on Sr1-xCax Co2P2 powder samples mainly in a zero applied field. The end member compound, SrCo2P2, is found to be paramagnetic down to 19 mK. As x increases, such a paramagnetic ground state is observed down to 1.8K until x = 0.45. Then, as x increases further, a short-range antiferromagnetic (AF) ordered phase appears at low temperatures for 0.48 ≤ x ≤ 0.75, and finally, a long-range AF ordered phase is stabilized for x > 0.75. The internal magnetic field of the other end member compound, CaCo2P2, is well consistent with that of the A-type AF order state, which was proposed from neutron scattering experiments. The phase diagram determined with μ+SR is different from that proposed by macroscopic measurements. For an isostructural compound, LaCo2P2, static magnetic order is found to be formed below

The ThCr2Si2-type layered compound SrCo2P2 shows an itinerant-electron metamagnetic transition at high magnetic field. To investigate substitution effects on the itinerant metamagnetic transition, we synthesized Sr[1-x]LaxCo2P2 and SrCo2(P[1-x]Gex)2 and measured their magnetic properties, including magnetizations under pulsed high magnetic fields. We have revealed a strong x dependence of the metamagnetic transition which is consistent with the band theory describing the physical properties in metals., 20th International Conference on Magnetism, ICM 2015