CN107601439B - A kind of MnTe nanowire and preparation method thereof - Google Patents

Abstract

The invention provides a MnTe nanowire. The MnTe nanowire prepared by the preparation method disclosed by the invention has good morphology and monodispersity through scanning electron microscope observation, and its diameter is 50-200nm, and its longitudinal length is 2-10μm Through X-ray diffraction, it is concluded that the MnTe nanowire prepared by the present invention has a hexagonal crystal structure, and the magnetic measurement shows that the MnTe nanowire exhibits antiferromagnetic properties.

Description

A kind of MnTe nanowire and preparation method thereof

technical field

The invention relates to the field of antiferromagnetic nanomaterials, in particular to a preparation method of MnTe nanowires.

Background technique

As an important part of nanotechnology, nanowires refer to one-dimensional structures that are limited to less than 100 nm in lateral structure. Nanowires have unique physical and chemical properties that other bulk materials do not have, such as quantum size effect, surface effect, macroscopic quantum tunneling effect, etc. Due to these unique properties, nanowires are used in light sensors, temperature sensors, rectifiers, photocopiers, It has a wide range of applications in inorganic coatings and piezoelectric transmission devices. Especially since the 20th century, the research on nanowires has developed rapidly, and with the deepening of nanowire research, nanowires of new materials are also emerging. For example, Professor Lieber's research group at Harvard University has prepared molybdenum selenide nanowires and studied its structure and electronic properties by tunneling microscopy (L.Venkataraman, CMLieber.Phys.Rev.Lett., 1999,83(25): 5334-5337); (Fe _1-x Co _x ) ₂ P magnetic nanowires developed by Yang et al. have a coercivity of 5.74kOe at 10K, but the nanowires are short in length, only about 2-4μm , which greatly limited its application (WWYang, XMWu, YSYu, et al. Nancosale, 2016, 8(36): 16187-16191); Chen et al. achieved a novel approach by doping MoS with CdS and Cu _{2 -x} MoSe ₂ -CdS, Cu _2-x S-MoSe ₂ nanowires formed by S form composites, which increase their longitudinal lengths while maintaining the nanometer size of CdS and Cu _2-x S (JZChen, XJWu, et al.J. Am. Chem. Soc., 2017, 139(25):8653-8660).

With the continuous development of semiconductor materials and memory materials, the demand for antiferromagnetic materials is also increasing. However, the current research on nanowires is mostly focused on the research on ferromagnetic nanowires, and the research on antiferromagnetic nanowires is less. Moreover, the morphology and monodispersity of the currently prepared antiferromagnetic nanowires are not very good, which limits their application in semiconductor materials and storage materials. Therefore, antiferromagnetic nanowires with uniform morphology and good monodispersity have been prepared. Nanowires are crucial.

SUMMARY OF THE INVENTION

The invention discloses a MnTe nanowire with good morphology and monodispersity and a preparation method thereof.

A preparation method of MnTe nanowire, comprising the steps:

Mixing the Mn-containing solution and the Te-containing suspension to obtain a reaction solution, and under the protection of an inert gas, the temperature is uniformly heated to 350-400 ° C to react to obtain MnTe nanowires;

Wherein, in the reaction solution, the ratio of the amount of Mn to Te is 1:(0.5-1.8).

Preferably, in the preparation method, the reaction solution is heated to 350-400° C. at a constant rate of (2-5)° C./min, and then incubated for 1-3 hours.

Preferably, in the preparation method, the Te source is dissolved in trioctylphosphine, and the Te-containing suspension is obtained by ultrasonication; the Mn source is dissolved in oleyl amine and stirred evenly to obtain the Mn-containing suspension solution.

Preferably, in the preparation method, the Mn-containing solution is heated to 100-120° C. under the protection of an inert gas, and then kept for 20-30 min, and the Te-containing suspension is added to it and mixed to obtain the reaction solution.

Preferably, the preparation method further includes the steps of washing and drying the MnTe nanowires.

Preferably, in the preparation method, the inert gas is nitrogen or argon.

Preferably, in the preparation method, the Mn source is manganese acetylacetonate; the Te source is tellurium powder.

A MnTe nanowire whose crystal form is a hexagonal crystal structure. .

The technical scheme of the present invention has the following advantages:

1. The present invention provides a kind of MnTe nanowire, the MnTe nanowire prepared by the preparation method disclosed in the present invention has good morphology and monodispersity through scanning electron microscope image observation, and its diameter is 50-300nm, and its longitudinal length is 50-300 nm. Adjustment between 2-10μm;

Through X-ray diffraction, it is obtained that the MnTe nanowire prepared by the present invention has a hexagonal crystal structure.

2. The present invention provides a method for preparing MnTe nanowires, which comprises mixing a Mn-containing solution with a Te-containing suspension to obtain a reaction solution, and under the protection of an inert gas, the temperature is uniformly heated to 350-400° C. to react to obtain MnTe nanowires. ; The process is simple, easy to implement, and has good application prospects.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

1-3 is the X-ray diffraction pattern of the MnTe nanowires obtained in Example 1-3 respectively;

4 and 7 are respectively the scanning electron microscope images of the MnTe nanowires obtained in Examples 1 and 3;

5 and 6 are respectively the scanning electron microscope images of the MnTe nanowires obtained in Example 2 at different resolutions;

8-10 are respectively the hysteresis loop diagrams of the MnTe nanowires obtained in Examples 1-3 at a low temperature of 5K.

Detailed ways

The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1

The present embodiment provides a MnTe nanowire, obtained by the following preparation steps:

(1) 2.8mmol of Mn (acac) ₂ and 30mL oleyl amine were added to the four _- necked flask equipped with temperature regulator and magnetic stirrer, stirred for 20min to obtain a solution containing Mn, and be warming up to 100 under N protection ℃, keep warm for 30min;

(2) 1.4 mmol of Te elemental powder was dissolved in 5 mL of trioctylphosphorus (TOP), and ultrasonicated for 30 min to obtain a suspension solution containing Te;

(3) The suspension solution containing Te was injected into the solution containing Mn, and the temperature was raised to 400 °C at a heating rate of 5 °C/min under nitrogen protection, the reaction was kept for 1 h, and the heat source was turned off. The MnTe nanowires can be obtained by centrifuging and washing three times, and then by natural drying.

Example 2

The present embodiment provides a MnTe nanowire, obtained by the following preparation steps:

(1) 2.8mmol Mn (acac) ₂ and 30mL oleyl amine are added in the four _- necked flask equipped with temperature regulator and magnetic stirrer, stir 30min, obtain the solution containing Mn, be warming up to 100 under N protection ℃, keep warm for 20min;

(2) 2.4 mmol of Te elemental powder was dissolved in 5 mL of trioctylphosphorus (TOP), and ultrasonicated for 30 min to obtain a suspension solution containing Te;

(3) The suspension solution containing Te was injected into the solution containing Mn, and the temperature was raised to 400 °C at a heating rate of 2 °C/min under nitrogen protection, and the reaction was kept for 2 h, and the heat source was turned off. The MnTe nanowires can be obtained by centrifuging and washing three times, and then by natural drying.

Example 3

The present embodiment provides a MnTe nanowire, obtained by the following preparation steps:

(1) 2.8mmol of Mn (acac) ₂ and 30mL oleyl amine were added to the four-necked flask equipped with temperature regulator and magnetic stirrer, stirred for 20min to obtain a solution containing Mn, and heated to ₁₂₀ under N protection ℃, keep warm for 20min;

(2) 3.6 mmol of Te elemental powder was dissolved in 5 mL of trioctylphosphorus (TOP), and ultrasonicated for 30 min to obtain a suspension solution containing Te;

(3) The suspension solution containing Te was injected into the solution containing Mn, and the temperature was first heated to 120 °C under nitrogen protection, and then heated to 350 °C at a constant rate of 5 °C/min, and the reaction was kept for 3 hours. The product was washed three times by centrifugation with absolute ethanol and n-hexane, and then naturally dried to obtain MnTe nanowires.

Effect verification example

1. Structural Characterization Detection

The MnTe nanowires prepared in Examples 1-3 were characterized by X-ray diffractometer (XRD).

Figure 1-3 shows the X-ray diffraction pattern of the MnTe nanowires obtained in Example 1-3;

The XRD pattern of the MnTe nanowire in the above-mentioned embodiment is consistent with the peak shape of MnTe (label: JCPDS18-0814) in the standard card library, indicating that the prepared MnTe nanowire is a hexagonal crystal structure; Different proportions of Te all generate MnTe phase.

2. Elemental composition and content detection

The elemental composition and content of the MnTe nanowires prepared in Examples 1-3 were tested by energy dispersive X-ray spectrometer (EDX).

Through X-ray energy spectrum detection: the mole percentage of Mn in the nanowires prepared in Example 1 is 54.38%, and the mole percentage of Te is 45.62%;

The mole percentage of Mn in the nanowires prepared by Example 2 is 50.26%, and the mole percentage of Te is 49.74%;

The mole percentage of Mn in the nanowires prepared in Example 3 is 51.65%, and the mole percentage of Te is 48.35%.

3. Morphology Characterization Detection

Scanning electron microscope (SEM) was used to test the morphology of the MnTe nanowires prepared in Examples 1-3.

Figures 4 and 7 show the scanning electron microscope images of the MnTe nanowires obtained in Examples 1 and 3, respectively; the MnTe nanowires prepared in Example 1 have a diameter of 80-120 nm and a length of 2-5 μm; prepared in Example 3 The obtained MnTe nanowires have a diameter of 100-200 nm and a length of 3-7 μm;

Figures 5 and 6 are respectively SEM images of the MnTe nanowires obtained in Example 2 at different resolutions; the MnTe nanowires prepared in Example 2 have a diameter of 50-100 nm and a length of 8-10 μm;

The average length of the MnTe nanowires prepared in Examples 1-3 is all greater than 5 μm, and the diameter is about 100 nm.

At the same time, it can be clearly seen from Figures 4-7 that the MnTe nanowires prepared in Examples 1-3 are uniform in thickness and have good morphology and monodispersity. Among them, the length of the nanowires in Example 2 exceeds 10 μm.

4. Magnetic detection

The hysteresis loops of the MnTe nanowires prepared in Examples 1-3 at 5K were characterized by a superconducting quantum interferometer (SQUID).

Figures 8-10 respectively show the hysteresis loops of the MnTe nanowires obtained in Examples 1-3 at a low temperature of 5K; the hysteresis loops show that the MnTe nanowires prepared in Examples 1-3 show antiferromagnetic properties Behavior.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (4)

1. a preparation method of MnTe nanowire, comprises the steps: Dissolve the Te source in trioctylphosphine, ultrasonically obtain a suspension containing Te; dissolve the Mn source in oleylamine, stir evenly to obtain a solution containing Mn, and place the solution containing Mn under the protection of an inert gas After warming up to 100-120°C, keep the temperature for 20-30min, add the suspension containing Te into it and mix to obtain a reaction solution, under the protection of an inert gas, the reaction solution is heated at a rate of (2-5)°C/min After heating at a constant speed to 350-400°C, the reaction is kept for 1-3h to obtain MnTe nanowires; Wherein, in the reaction solution, the ratio of the amount of Mn to Te is 1:(0.5-1.8). 2. The preparation method of claim 1, further comprising the steps of washing and drying the MnTe nanowires. 3. The preparation method according to claim 1 or 2, wherein the inert gas is nitrogen or argon. 4. The preparation method of claim 1, wherein the Mn source is manganese acetylacetonate; the Te source is tellurium powder.

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