title: Set custom scientific notation y tick on log-plot
body: <p>I am trying to set custom ticks for my plots but I'm struggling a lot, I tried solution from several other thread  and none works :/ I need to do two distinct plots and I have some issues on them.</p>
  <p>I would like to have custom y ticks that does 5x10^-3, 2x10^-3, 1x10^-3, 5x10^-4... (multiple of 1,2,5 and in scientific notation)</p>
  <p>On both plot I can't seem to modify the ticks. (I thought the issue for the second plot that it was because the minor ticks where invisible, but even after putting them visible I couldn't modify them). A solution where I set ticks &quot;half worked&quot;, meaning that I couldn't set them in scientific notation</p>
  <p><a href="https://i.stack.imgur.com/TKsEj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TKsEj.png" alt="enter image description here" /></a>
  <a href="https://i.stack.imgur.com/H2uMt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/H2uMt.png" alt="enter image description here" /></a></p>
  <p>Any help would be very appreciated :)</p>
  <pre class="lang-py prettyprint-override"><code>plt.rc('text', usetex=True)  
  plt.rc('font', family='serif')  
  plt.rcParams['figure.dpi'] = 600
  plt.rcParams[&quot;figure.figsize&quot;] = (4,2.1)
  matplotlib.rcParams.update({'font.size': 13})
  
  plt.plot([100,200 ,300 ,400 ,500 ,1000,1500,2000],[0.001378,0.000817,0.000627,0.000533,0.000457,0.000317,0.000240,0.000206])   
  
  plt.grid(axis='y', linestyle='dotted', which='minor')
  plt.grid(axis='x',linestyle='dotted')
  plt.yscale('log')
  plt.yticks([0.00005])
  plt.show()
  </code></pre>